Method and device for modifying surface-based image data of a three-dimensional geometric model

Abstract

The invention relates to a method for modifying a model (M) in the context of an additively manufactured component, the method comprising the following steps: - creating a voxel grid (G, G1), - for a voxel (X, X1) in the voxel grid (G, G1): a) determining whether the relevant voxel (X, X1) is located inside or outside the model (M); and / or b) assigning indices (N) to a plurality of surface segments (S) of the model (M) and assigning the index (N) of the nearest surface segment (S) to the relevant voxel (X, X1); and / or c) determining the distance of the voxel (X, X1) to the surface of the model (M); - outputting the voxels (X, X1) and the information assigned to them. The invention also relates to a corresponding device, a control device for an additive manufacturing device and a corresponding manufacturing device, a modified data set and a manufacturing method.

Description

Technical Field

[0001] The invention relates to a method and a modification device for modifying surface-based image data of a three-dimensional geometric model, in particular for additively manufactured components. In addition, the invention relates to a control device for a manufacturing device for additively manufacturing components during a manufacturing process, and a corresponding manufacturing device, a data set including various data of the model, and a manufacturing method for additively manufactured components. Background Art

[0002] In recent years, the creation of (virtual) three-dimensional geometric models has become increasingly important. Such (virtual) models are not only indispensable for purely graphical representations, but also for the creation of real components by automated manufacturing methods. For example, with additive manufacturing methods, the component to be manufactured is first created as a model with a CAD program, which is then stored as surface-based information (usually an STL file), and then the component layers are created using this information so that the component can be formed layer by layer based on the model.

[0003] A serious disadvantage is that, especially for complex components, files with surface-based information can have a very large storage requirement and cannot be modified or can only be modified very poorly. If this surface-based information is present, for example, as a pure triangle mesh (e.g. in an STL file), it is very difficult to modify the model, especially with the help of Boolean operations such as joining, cutting or forming intersections. It is also difficult to export variables such as distances from the STL file.

[0004] On the other hand, these changes can also be easily achieved using implicit geometry (i.e. functions of shape elements). For example, common CAD programs usually provide basic elements such as cubes, cylinders or spheres, based on which more complex models can be formed using Boolean operations or other mathematical functions (such as chamfers). Very complex models can also be defined using simple trigonometric functions.

[0005] Based on implicit geometry, surface information or layer information (contours or grid patterns) with arbitrary resolution can also be generated, which makes it particularly suitable for manufacturing methods.

[0006] Finally, situations may also arise in which the implicit geometry of a component is not available at all, for example if the component has been converted into a (virtual) model by means of a 3D scanning method or if special geometries exist. Summary of the invention

[0007] The object of the present invention is to overcome the disadvantages of the prior art and to provide a method and a modification device by means of which the surface-based information of a model can be modified so that subsequent changes to the model can be made in a simple and fast manner. In particular, the object of the present invention is to optimize the computational effort and / or memory consumption required for subsequent changes to a model defined by the surface-based information. A particularly preferred object of the present invention is to be able to combine models exported as STL files or corresponding files with implicit geometry.

[0008] This object is achieved by a method according to claim 1, a corresponding modification device according to claim 10, a control device according to claim 11, a production device according to claim 12, a data set according to claim 13 and a production method according to claim 14, as well as a computer program product according to claim 15.

[0009] The method according to the invention is used to modify surface-based image data of a three-dimensional geometric model suitable for additive manufacturing of a component. Surface-based image data are well known in the prior art and include (especially only include) the above-mentioned surface-based information. The above-mentioned data are surface data of the model, which have geometric information about a plurality of surface segments (such as triangles), which together form the surface of the model.

[0010] Surface-based image data are therefore data that describe the surface of a 3D object, in particular without including its volume (only indirectly by arranging surface segments, which can also be referred to as "patches"). The surface segments are preferably grid coordinates (points) of a three-dimensional model, which are connected by means of (in particular straight) edges and in particular form polygons. The image data can also include other information, such as data about the surface normals of the surface segments. A well-known format for surface-based image data is the so-called "STL format", where the acronym "STL" originally stood for "stereolithography", but is now also interpreted as "Standard Triangle Language" or "Standard Tessellation Language (English "tessellation" = "subdivision surface")". The STL format describes the surface of a 3D object with the help of triangular patches. Each triangular patch is characterized by three vertices of a triangle and the associated surface normal. When observing a triangular surface, if the three vertices are arranged counterclockwise, the surface is assumed to be outside the volume. The surface normal always points outside the object. Even though a division into triangles is particularly advantageous, the image data need not necessarily be restricted to triangles.

[0011] In short, the image data includes information about the surface of the 3D object, but preferably does not include information about the implicit geometry of the object.

[0012] The method according to the invention comprises the following steps:

[0013] - creating a plurality of voxel grids, each of the plurality of voxel grids having a plurality of voxels, wherein each voxel grid encompasses and surrounds at least a portion of the surface segments,

[0014] -For a voxel in a voxel grid:

[0015] a) determining position information, which indicates whether the relevant voxel is located inside or outside the contour of the model, and assigning the position information to the relevant voxel; and / or

[0016] b) assigning individual indices to at least a portion of the surface segments of the image data, such that each indexed surface segment can be distinguished from all other indexed surface segments of the model by means of its index, and assigning the index of the nearest surface segment to the relevant voxel; and / or

[0017] c) determining the distance between the relevant voxel and the surface of the model, and assigning corresponding distance information to the relevant voxel;

[0018] - Output voxels and the information assigned to them.

[0019] As mentioned above, the image data includes surface segments, such as triangles. For ease of understanding, it can be assumed that the image data is composed of multiple triplets of point coordinates, each triplet representing three vertices of a triangle.

[0020] At least a portion of the surface segments, preferably all surface segments, are assigned a separate index. In order to completely modify the image data of the object, it is meaningful to assign a separate index to all surface segments. The index can be, for example, a continuous code or a separate string (such as an address). However, the index can also be a coordinate, such as the coordinate of the center of gravity or center of a certain surface segment.

[0021] For the allocation of voxels considered in the method it is preferred that at least a part of the surface segments are provided with indices and each indexed surface segment can be distinguished from all other indexed surface segments of the model by means of the index. Hence, all indices should be different from each other.

[0022] The term "voxel" is composed of the English words "volume" (vox) and "element" (el) and in computer graphics refers to a grid element, i.e. a volume, in a three-dimensional grid. In two-dimensional grid graphics, the term "pixel" (standing for "picture element") has been established for image points. A voxel is the three-dimensional counterpart of a pixel. In the sense of the present invention, a voxel is a (especially cubic) volume element in a three-dimensional grid.

[0023] In this case, at least one grid ("voxel grid") is created, which has (in particular indexed) surface segments inside. The expression "encompasses and surrounds" is intended to indicate that the grid extends beyond the surface segment, but is not only located outside the surface segment (like an included surface layer), but is also defined in the volume of the surface segment (i.e. also extends through the surface segment). Preferably, the relevant surface segment (in particular all surface segments of an object) is surrounded by a three-dimensional boundary ("bounding box"), and the volume surrounded by this boundary is completely divided into voxels by the grid.

[0024] For the voxels of the voxel grid, i.e. preferably for each individual voxel, specific steps are now performed. In this case, it is possible to group voxels together for which the steps result in clearly identical information. For example, these are voxels to which the same value is assigned. This happens less frequently for distance information, but more frequently for index and position information. Preferably, the different information (distance, position information, index) can be grouped separately.

[0025] First, determine the position information of the relevant voxels. This position information indicates whether the relevant voxels are located inside or outside the contour of the model (i.e., the 3D object). If the image data originates from an STL file, it is possible to infer, for example, where the outside and where the inside are based on the arrangement of the vertices. For this purpose, the surface normal of the surface segment can also be used. In particular, the sign can be directly determined by the surface normal. Another very reliable but computationally intensive method is to determine all the intersections of a line from the point under consideration to a point known to be located outside. Another preferred method is to determine the contour in the plane where the point is located (the intersection of the plane and the component surface), and then determine the sign based on the contour by the winding method. However, if only the position information needs to be filled for a voxel model or a grid graphic, this can also be done, for example, by "flood filling". For this purpose, it is possible to start with a voxel known to be inside. For this purpose, the normal of the triangle can be used, and the point immediately adjacent to the inside of the triangle is selected. Starting from this point, if all adjacent points are not intersected by the triangle, they are filled. Repeat the same operation for adjacent points until all relevant voxels are processed.

[0026] In a preferred simple case, the position information can take two values, a first value (e.g. "-" or "true") if the voxel is located inside the model, and a second value (e.g. "+" or "false") if the voxel is located outside the model. A voxel is located inside (outside) the model when the vast majority of the voxel is located inside (outside) the model. Alternatively, a voxel is located inside (outside) the model when the center of the voxel is located inside (outside) the model. It can also be defined whether the voxels through which the surface segment extends (i.e., the voxels intersecting the surface segment of the model) must be assigned the same position information as the voxels inside or outside the model. That is, for example, it can be defined that the position information of the voxels intersecting the surface segment of the model adopts the same value as the voxels located inside the model (e.g. "-" or "true"). Alternatively, it can be defined that the position information of the voxels intersecting the surface segment of the model adopts the same value as the voxels located outside the model (e.g. "+" or "false").

[0027] In another preferred case, the position information can take three values, depending on whether the voxel is (completely) inside or outside the model, or whether the surface of the model intersects the voxel (i.e., the voxel is on the surface of the model). In this case, if the voxel is inside the model, the position information can be a first value (e.g., "-"), if the voxel is outside the model, the position information can be a second value (e.g., "+"), and if the surface segment extends through the voxel (i.e., the voxel intersects the contour or surface segment of the model), the position information can be a third value (e.g., "0").

[0028] This position information is then assigned to the relevant voxel. This can be achieved, for example, by storing it directly as information of the voxel or, for example, by linking it to the relevant voxel by means of a pointer. In three-dimensional computer graphics, voxels have coordinate and color information. For example, the position information can be stored in the color channel of such a voxel.

[0029] As a supplement or alternative to the position information (preferably supplemented), the index of the nearest surface segment is assigned to the relevant voxel. This assignment can be performed based on the position information (i.e., for example, also in the color channel). In the prior art, it is well known how to determine the distance from a point (voxel) to a surface. In geometry, the distance is always calculated according to the shortest distance. The index of the surface segment on the straight line of the shortest distance between the marked surface segment and the relevant voxel is assigned to the relevant voxel. However, the assignment of the index can also be performed without measuring the distance, for example, by the following method: the index of the relevant surface segment is assigned to all voxels in the bounding box around the surface segment, and only the voxels assigned two or more indices are performed in more detail. "Distance" can be understood in particular as a square distance, which simplifies the calculation based on the Pythagorean theorem in particular. Preferably, a voxel intersecting with multiple surface segments is not only assigned a single index, but also assigned a list of indices containing all surface segments intersecting with the voxel. When checking the indices of neighboring voxels, the minimum distance to all surface segments having an index is then preferably determined.

[0030] Particularly preferably, a voxel is assigned both position information and an index.

[0031] In addition or as an alternative to the position information and / or the index, the distance of the relevant voxel to the model surface is determined. This has already been described in the previous paragraph. The assignment of the corresponding distance information to the relevant voxel can correspond to the assignment of the position information, for example in the color channel. Particularly preferably, the index of the nearest surface segment is assigned to the voxel, the distance between the voxel and the indexed surface segment is calculated, and the calculated distance and the index of the indexed surface segment are assigned to the voxel.

[0032] The voxels and the information assigned to them are then output, e.g. for storage or for further calculations. Basically, voxels can be used to determine implicit geometry or directly to perform Boolean operations. If the voxels contain information about distances, they can already describe the implicit geometry. As with implicit surfaces described by functions, Boolean operations can be implemented by simple min / max operations, e.g. minimizing the distance between two different components for joining.

[0033] The modification device according to the present invention is used to modify surface-based image data of a three-dimensional geometric model suitable for additive manufacturing of a component. Here, the image data includes surface data of the model, which surface data has geometric information about a plurality of surface segments, which together form the surface of the model. The modification device includes the following components:

[0034] - a data interface designed to receive image data,

[0035] a confinement unit designed for creating a plurality of voxel grids each having a plurality of voxels, wherein each voxel grid encompasses and surrounds at least a portion of the surface segments,

[0036] - a processing unit designed to:

[0037] a) determining position information indicating whether the relevant voxel is located inside or outside the contour of the model, and assigning the position information to the relevant voxel and / or

[0038] b) assigning the index of the nearest surface segment to the relevant voxel, wherein the modification device comprises for this purpose an indexing unit which is designed to assign individual indices to at least some of the surface segments, such that each indexed surface segment can be distinguished from all other indexed surface segments of the model by means of its index,

[0039] and / or

[0040] c) determining the distance of the relevant voxel to the surface of the model and assigning corresponding distance information to the relevant voxel,

[0041] A data interface which is designed to output the voxels and the information assigned to them.

[0042] With these modified image data, the model can now be modified, for example, to provide it with a structure that a subsequently created component also has.

[0043] In the above, the working principle of the individual components has been described in detail within the scope of the method. Preferably, the modification device is designed to carry out the method according to the invention.

[0044] The control data for controlling a manufacturing device for additive manufacturing according to the invention are created from the modified image data. In this case, the modified (and if necessary processed) image data are preferably converted again into surface-based image data and control data are created based on this. Creating control data from surface-based image data (or other image data) is known in the prior art. In addition to the control data, variables (e.g., the distance to the bottom or top of the component) can also be determined based on the modified image data. Control data and / or additional control data can be created based on the variables determined from the modified image data.

[0045] A control device according to the present invention comprises a modification device according to the present invention, which is used for a manufacturing device of an additively manufactured component during a manufacturing process. During the manufacturing process, a forming material, preferably comprising metal powder, is formed layer by layer in a forming field, and correspondingly, between two layers of material applied, selective solidification of the forming material is achieved by irradiating the forming material with at least one energy beam achieved by means of an irradiation device.

[0046] A manufacturing device according to the present invention is used for additive manufacturing of at least one component in an additive manufacturing process, the manufacturing device comprising at least:

[0047] - a supply device for applying a material layer of forming material into a forming field in the processing chamber,

[0048] - an irradiation device for selectively curing the shaping material by irradiating it with at least one energy beam, in particular between the application of two material layers, and

[0049] - A control device according to the invention.

[0050] A data set according to the invention, comprising surface data of a model and data of a plurality of voxels and information assigned to them, which information is created with the aid of a method according to the invention, the data set in particular comprising control data for controlling a manufacturing device for additive manufacturing, which control data is generated based on the voxels with the aid of the method according to the invention.

[0051] In the production method according to the invention for additively manufacturing a component, a forming material, preferably comprising metal powder, is formed layer by layer in a forming field, and selective curing is performed between the material layers to which two layers of the forming material are applied, in particular by irradiating the forming material with at least one energy beam based on image data, which are modified by means of the method according to the invention. In this case, in order to create the layer structure of the component, the energy beam is moved over the forming field along a plurality of parallel curing paths in a specified area of ​​the layer structure according to corresponding control data (based on the modified image data).

[0052] The present invention can be implemented in particular in the form of a computer unit with suitable software. For this purpose, the computer unit can, for example, have one or more microprocessors working in cooperation, etc. In particular, it can be implemented in the form of suitable software program components in the computer unit. The advantage of the implementation mainly based on software is that the computer unit used so far, especially the control device of the manufacturing device, can also be transformed in a simple way by software or firmware update, so as to work in the manner according to the present invention. In this regard, the purpose is also achieved by a corresponding computer program product, which has a computer program that can be directly loaded into a storage device of a computer unit (especially a control device), and the computer program has program segments so that when the program is executed in the computer unit, all steps of the method of the present invention are executed. In addition to the computer program, this computer program product can also include other components, such as documents and / or other components, and hardware components, such as hardware keys (software protectors, etc.) for using the software. In order to be transmitted to the computer unit and / or stored on or in the computer unit, a computer-readable medium can be used, such as a memory stick, a hard disk or other removable or fixed data carrier, on which program segments of a computer program that can be read and executed by the computer unit are stored.

[0053] Other particularly advantageous designs and improvements of the present invention are derived from the dependent claims and the following description, wherein the independent claims of one category of claims can also be improved similarly to the dependent claims and embodiments of another category of claims, and in particular, the individual features of different embodiments or variants can also be combined into new embodiments or variants.

[0054] According to a preferred method, voxels assigned the same index and / or the same position information are grouped together. This simplifies and speeds up subsequent calculations, since sometimes only a single calculation needs to be performed for the entire group, i.e. all voxels of the group together. Preferably, the voxels assigned distance information are considered as individual voxels. Therefore, these voxels are preferably not associated with other voxels in the group.

[0055] Preferably, the information assigned to a voxel is directly assigned to the voxel or the group. This means that the voxel or the group each comprises the information assigned to them, or the voxel (or the group) is assigned a hint, such as a pointer, to this information.

[0056] According to a preferred method, a plurality of voxel grids with different resolutions and / or different sizes are created, and distance information and / or indices and / or position information are assigned to the relevant voxels depending on which voxel grid the voxel is located in. It is likely that only indices are assigned to the voxels of a certain voxel grid, while position information and / or distances are preferably assigned to the voxels of another voxel grid together with the indices. It is preferred that at least the first voxel grid and the second voxel grid are defined in such a way that the first voxel grid has a coarser resolution and / or is larger than the second voxel grid, wherein in the latter case the second voxel grid is preferably located within the first voxel grid.

[0057] Preferably, the assignment of information to the voxels depends on a limit value associated with the distance value. In particular, voxels within the limit value (i.e., with a distance less than the limit value) are assigned a distance value (and preferably also position information and / or an index), and voxels outside the limit value are only assigned an index and / or position information. However, a voxel grid can also be used as a boundary area and therefore essentially assumes the task of such a limit value. If a limit value and multiple voxel grids are used simultaneously, a single limit value can be completely applicable to each voxel grid. In a preferred practical application, only the position information and / or the index are stored in the voxels of the coarse voxel grid, and the distance information (and, if necessary, the index and / or the position information) are stored in the voxels of the fine voxel grid.

[0058] With regard to the above-mentioned limit values, according to a preferred method, only voxels whose distance to the surface is less than a predetermined maximum distance are assigned distance information. The predetermined maximum distance is then the limit value. Preferably, the maximum distance in the first voxel grid is greater than the maximum distance in the second voxel grid. Preferably, voxels in the first voxel grid are assigned position information and / or index, but not distance information. Preferably, each voxel assigned distance information is also assigned at least position information.

[0059] According to a preferred method, in order to determine the distance and / or index and / or position information: a voxel grid is scanned voxel by voxel, a relevant value is determined and assigned to each voxel in the voxel grid, and when determining the distance, the shortest distance to the model surface is preferably determined starting from each scanned voxel.

[0060] According to a preferred method, to determine the distance and / or index and / or position information, the model is scanned surface segment by surface segment and for the voxels surrounding the respective surface segment, a value associated with each voxel is determined and assigned to the associated voxel.

[0061] Here, it is preferred that: within the range of the first voxel to be checked, the voxels surrounding the voxel are checked to determine whether these voxels are assigned the index of another surface segment different from the first voxel. If so, the distance from the first voxel to the other surface segment is also measured, and it is determined whether the distance is less than the distance to the initially assigned surface segment. In this way, the error in assigning information is minimized.

[0062] According to a preferred method, the surface-based image data (or "surface data") of the model are grid coordinates of a three-dimensional data model, in particular designed for manufacture by means of an additive manufacturing method. Preferably, these surface data are data for stereolithography or standard triangle language (or standard subdivision surface language). For example, preferably an STL file is used.

[0063] According to the preferred method, the output voxels and the information assigned to them are used to modify the model. This is a very important possible application of the method. In the introduction, it was mentioned that surface-based data are not optimal for subsequent changes to components or cannot be used at all. Now, with the voxels that are additionally provided with information, effective modifications of components can be performed, for example, the components can be structured or modified with the help of other objects, especially when Boolean operations are used. Preferably, the method is applied to multiple models here, and these models influence each other in particular with the help of Boolean operations. In this case, in particular two models are combined (logical "or"), subtracted from each other (logical "and", the voxels of the model to be subtracted are input inversely), or the intersection of the models is formed (logical "and"). It should be noted that the model can completely be an implicit surface described as a mathematical function. Then, these distance functions can also be used to perform operations. For example, the combination of model A and model B can be calculated, where A and B are distance functions. Here, A and B can be pure mathematical functions or distances to the grid calculated with the help of information from the voxel model. The modification of the model can be nested arbitrarily.

[0064] The model can therefore in particular be subsequently expanded or structured.

[0065] According to a preferred method, the voxels of the voxel grid are assigned the index of the surface segment. According to the invention, this surface segment is the corresponding nearest surface segment. Preferably, this applies to the finest voxel grid, i.e. the voxel grid with the finest resolution. However, here, only the grids in the edge area, i.e. in the area of ​​the surface segment, are linked to the index.

[0066] Then, perform the following steps for multiple points:

[0067] - select points in a voxel of a voxel grid,

[0068] - determining the distance of the point to the surface segment assigned the associated index,

[0069] In terms of selection, a certain point can be preselected and checked whether it is located in a voxel of the voxel grid. If so, the method is performed, if not, the point is assigned, for example, position information. However, it is also possible to consider a certain voxel and intentionally select a point in this voxel.

[0070] Preferably, the following steps are also performed:

[0071] - check if the index is different from the index of the neighboring voxel, if so: determine the distance of the point to the surface segment assigned the relevant index of the neighboring voxel,

[0072] - Compare the determined distances and select the smallest distance.

[0073] This allows for a more precise determination of the distance of a point to the surface.

[0074] According to a preferred embodiment of the method, distance information is also assigned to the voxels in the voxel grid. Preferably, the distance of the point to the surface segment is determined only when the distance of the voxel read from the distance information is lower than a maximum distance. The maximum distance is, for example, a defined threshold value, which can be selected in particular according to the voxel size and / or the surface characteristics. Thus, for example, if the magnitude of the distance information stored in the voxel is lower than the maximum value (defined threshold value), an exact calculation of the distance is performed. Therefore, in this case, "distance determination" means performing an exact calculation of the distance. Further preferably, if the distance of the voxel that can be read from the distance information exceeds the maximum distance (defined threshold value), the distance information and / or position information of the voxel is assigned to the point. Therefore, in this case, "distance determination" means determining the distance of the voxel that can be read from the distance information (without performing an exact calculation).

[0075] According to a preferred embodiment of the method, the voxels in the voxel grid are also assigned position information, which is preferably subsequently assigned to the point. In the case where the position information indicates the position of the voxel on the edge, corresponding position information is also calculated for the point.

[0076] Therefore, a function F(P) is used which provides distance and preferably also position information for a point P(x, y, z) in space by means of a voxel model. Such functions are generally known, wherein the distance to the surface element is determined around this point, for example, by a simple trigonometric length determination. The invention is special in that the index information is used to select specific surface segments, thereby greatly reducing the calculation effort. Thus, the distance between the surface of the model and a point P(x, y, z) in 3D space can be determined in a resource-saving manner based on the voxel grid. The determined distance can be used to generate commands (slices, support structures, etc.).

[0077] Here, for a point P, the voxel V with the finest resolution in the grid is preferably searched. In addition to the index, position information L can be assigned to the voxel, which simplifies the determination of whether the point is located outside or inside the component. As described above, searching for a voxel means: assigning point P to the voxel in which point P is located; or if point P is not in the voxel, assigning point P to the nearest voxel. Therefore, preferably searching for the voxel with the finest resolution means, for example: assigning a point P that is located in two voxels at the same time to the voxel with the finest resolution of the two voxels in which point P is located. In the following, the voxel that is searched first or to which point P is assigned first is also called the "origin voxel (Heimatvoxel)".

[0078] This can further reduce the computational effort if the voxel also includes distance information and the calculation of a point is performed only when the distance of the voxel to the nearest surface element is less than a certain value. Otherwise, the point can be assigned the distance information of the voxel or its position information.

[0079] Once the distance from P to the surface element (of the nearest voxel) is calculated, the nature of the point is basically determined. However, there may be a situation where another surface element is closer to the point, for example, for an edge point of a voxel. Then, the index of this other surface element must also be assigned to the neighboring voxel. Here, it is preferred that if the index of the neighboring voxel is different from the index of the "origin voxel", the distance from P to all surface elements pointed to by the index of the neighboring voxel is calculated. Then, the minimum value of the measured distances is output as the distance value of the point.

[0080] However, the distance of P can also be calculated by interpolation based on the distance information of the "origin voxel" and / or the distance information of the adjacent voxels, preferably by bilinear interpolation. In particular, if no distance information is assigned to the "origin voxel", the distance of P can be calculated by interpolation based on the distance information of the adjacent voxels.

[0081] The modified model (i.e., a modification of the model for which the surface data was originally available) essentially comprises a distance function from each point to the surface. Here, the distance function consists of a mathematical function and a distance function in the sense of the above description. Points far from the edge do not need to be accurately covered by the distance function. Here, simple position information (inside / outside) may be sufficient. In a further step, the distance function of the modified model can be used to directly determine the contour of an arbitrary cutting plane or cutting surface (for example, for a printer that can perform non-planar printing) or to generate a grid. Depending on the system used, this can save time and effort. For this purpose, there are known algorithms such as Marching Square or Dual Contouring.

[0082] In practice, this works like this: a point in a voxel that has distance information assigned to it is selected. If the point is located in multiple voxels of different grids, the voxel of the finest grid should be selected. If the point is located in the center of a voxel, the point can simply be assigned the distance information of the voxel. However, this rarely happens and the check associated with this may take longer than the distance calculation for the point. If the distance information of the voxel (where the point is located) is below a certain threshold, the distance of the point to the surface element with the same index is determined. If the distance information exceeds the threshold, it is assigned to the point and no separate distance calculation is performed.

[0083] Without assigning an index to a voxel, the distance between a point and the model can be calculated "on the fly", i.e. without accessing the information contained in the voxel. In particular, this calculation can be performed by means of an alternative (e.g. simplified) function ("substitution function"). Alternatively, the distance between a point P(x, y, z) and a bounding box can be calculated. Furthermore, the distance between a point and a polynomial function describing a similar (e.g. simplified) form to the model can be calculated in the same way. The distance between a point and the center of the model can also be determined.

[0084] According to a preferred method, the output voxels and the information assigned to them are used to create a section plane of the model, in particular for an additive manufacturing method. Since the surface data of the model are often recreated for this purpose, it is particularly advantageous to create a modified section plane of the model in the above manner.

[0085] According to a preferred method, the output voxels and the information assigned to them are used to generate control data for a production device for additively producing a component in a production process. In this production process, a forming material, preferably comprising a metal powder, is formed layer by layer in a forming field and the forming material is selectively solidified between the material layers of two applied forming materials by irradiating the forming material with at least one energy beam.

[0086] In practice, as described above, the image data are preferably a combination of coordinates of the vertices of polygons (surface segments), in particular triangles, and, if necessary, surface normals of the surface segments or directions of the surface normals (e.g., unit vectors pointing outward). These image data describe the external shape of the object and indicate that everything within the acquired surface must belong to the volume of the object. In this case, the volume of the object and the surrounding space is divided into a plurality of voxels (voxel grid), and these voxels are assigned at least the index and / or position information of the nearest surface segment (inside, outside or on the edge).

[0087] It should be noted that the entire object does not need to be meshed with voxels. It is basically sufficient to define a certain area of ​​the object to be modified (e.g. structured) and then have it meshed with voxels. Therefore, it can also be assumed that a "structured area" is defined and this area is meshed with voxels.

[0088] Position information may be sufficient to modify the model. With the voxels assigned position information, it can be decided how these voxels should be treated, for example when performing Boolean operations relative to a second object. For example, if the second object is a grid with a regular structure and if it should be cut out (or form an intersection) from the model, for each voxel of the model it is only necessary to check whether it lies on a voxel of the object, and if so, remove the voxel (when cutting out) or keep it (when forming an intersection), provided that its position information indicates that the voxel is inside the model. Voxels outside the model (given by the position information) are removed. All remaining voxels of the model then form the modified model.

[0089] When only the position function is used, a voxel model is obtained that distinguishes between filled or unfilled voxels, and its surface can be further improved. This can be achieved in particular by distance information and indices. Therefore, the present invention provides the possibility of generating a surface implicitly described by a distance field. As a result, an implicit geometry with a precisely defined surface can be generated. Here, the distance information with which the surface can be reconstructed is stored in the voxel. Boolean operations can be performed very easily using this distance information. For example, the combination of two objects is to minimize two distance information. The difference between the two objects can be represented by max(a, -b) using the distance information a and b of the two objects. In the sense of the present invention, the index is very advantageous for being able to calculate the exact distance, i.e. for any point that does not necessarily have to be located on the voxel grid (i.e., located anywhere between the voxel center points). BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The present invention will be described in more detail below with reference to the accompanying drawings by means of embodiments. In the various drawings, the same components are provided with the same reference numerals. The accompanying drawings show:

[0091] Figure 1 A schematic partial cross-sectional view showing an embodiment of a manufacturing device for additive manufacturing having a modified device of the present invention;

[0092] Figure 2 showing a model and a voxel grid encompassing and surrounding the model;

[0093] Figure 3 showing a model with voxels and different position information;

[0094] Figure 4 Two voxel grids of different fineness are shown;

[0095] Figure 5 shows voxels that are assigned different information depending on their location;

[0096] Figure 6 a two-dimensional illustration showing a fine grid in voxels with distance information and a coarse grid in voxels with only indices; and

[0097] Figure 7 A block diagram showing the method is shown. DETAILED DESCRIPTION

[0098] The following exemplary embodiments will be described with reference to a production device 1 for additively producing components in the form of a selective laser sintering device or a laser melting device, wherein it is once again explicitly pointed out that the present invention is not limited to selective laser sintering devices or laser melting devices.

[0099] Figure 1 Such a manufacturing device 1 is schematically shown. The manufacturing device has a processing chamber 3 or processing room 3 with a chamber wall 4, in which the manufacturing process is essentially carried out. In the processing chamber 3, there is a container 5 open upward with a container wall 6. The top opening of the container 5 forms a corresponding current working plane 7. The area of ​​this working plane 7 located within the opening of the container 5 can be used for forming the object 2 and is therefore called a forming field 8.

[0100] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. This base plate 11 closes the container 5 downwards and thus forms its bottom. The base plate 11 can be formed integrally with the carrier 10, but it can also be a plate formed separately from the carrier 10 and can be fastened to the carrier 10 or simply supported thereon. Depending on the specific forming material (i.e., for example, the powder used) and the type of manufacturing process, a forming platform 12 can be mounted on the base plate 11 as a forming support, on which the object 2 is formed. In principle, however, the object 2 can also be formed on the base plate 11 itself, which then constitutes the forming support.

[0101] The basic forming principle of the object 2 is as follows: first, a layer of forming material 13 is applied to the forming platform 12; then the forming material 13 is selectively solidified at the point where the part of the object 2 to be manufactured should be formed using a laser beam 22 as an energy beam; then the substrate 11 and therefore the forming platform 12 are lowered with the aid of the carrier 10, and a new layer of forming material 13 is applied and selectively solidified, and so on. Figure 1The object 2 formed in a container on a forming platform 12 is shown in an intermediate state, below the working plane 7. The object already has a plurality of solidified layers, which are surrounded by a still unsolidified forming material 13. Various materials can be used as forming material 13, preferably powders, in particular metal powders, plastic powders, ceramic powders, sand, filled or mixed powders or pasty materials, and optionally mixtures of a plurality of materials.

[0102] Unused shaping material 15 is located in a storage container 14 of the production device 1. By means of a coating machine 16 movable in a horizontal direction H, the shaping material can be applied in the form of a thin layer to the working plane 7 or the shaping field 8.

[0103] Optionally, an additional radiation heating device 17 is provided in the process chamber 3. The radiation heating device can be used to heat the applied shaping material 13 so that the irradiation device for selective curing does not need to introduce too much energy. This means that, for example, with the aid of the radiation heating device 17, a certain amount of basic energy can already be introduced into the shaping material 13, which is of course still lower than the energy required to melt or sinter the shaping material 13. For example, infrared radiators or VCSEL radiators can be used as radiation heating devices 17.

[0104] In order to perform selective curing, the manufacturing device 1 has an irradiation device 20, or more precisely, an irradiation device 20 with a laser 21. The laser 21 generates a laser beam 22, which is deflected by a deflection device 23 so as to scan the corresponding layer to be selectively cured along an irradiation path or track (hatching line) set according to the irradiation strategy and selectively introduce energy. Further, the laser beam 22 is focused on the working plane 7 in a suitable manner by a focusing device 24. Here, the irradiation device 20 is preferably located outside the processing chamber 3, and the laser beam 22 is guided into the processing chamber 3 via a coupling window 25 installed in the chamber wall 4 at the top of the processing chamber 3.

[0105] For example, the illumination device 20 may comprise not one but a plurality of lasers. Preferably, it may be a gas or solid-state laser or any other type of laser, such as a laser diode, in particular a VCSEL (Vertical Cavity Surface Emitting Laser) or a VECSEL (Vertical External Cavity Surface Emitting Laser) or a series of these lasers. Particularly preferably, within the scope of the invention, one or more unpolarized single-mode lasers are used, such as a 3 kW fiber laser with a wavelength of 1070 nm.

[0106] The control device 30 serves to control the units of the production device 1 and comprises a control unit 29 which actuates the components of the irradiation device 20 , namely here the laser 21 , the deflection device 23 and the focusing device 24 .

[0107] The control unit 29 also controls the radiation heating device 17 by means of suitable heating control data HS, controls the coater 16 by means of coating control data ST, and controls the movement of the carrier 10 by means of carrier control data TS, thereby controlling the layer thickness.

[0108] For the subsequent modification of the image data transmitted to the production device 1, a structure is provided, for example, which comprises a modification device 34. In this example, the modification device is designed to generate control data PS directly from the modified model.

[0109] The modification device 34 is used to modify the surface-based image data O of the three-dimensional geometric model M of the component 2. In this case, the image data O include surface data O of the model M, which have geometric information about a plurality of surface segments S, which together form the surface of the model M. In this case, the modification device 34 includes a data interface 35, which is designed to receive these image data O and to output voxels X, X1 and information N, L, A assigned to them. These voxels form an image data set, but the image data set is not (purely) surface-based. In addition, the data interface 34 can also be designed to output control data PS to the device 1 for additive manufacturing of the component 2.

[0110] Furthermore, the modification device 34 further includes an indexing unit 36 ​​, a limiting unit 37 and a processing unit 38 .

[0111] The indexing unit 36 ​​is designed to assign a single index N to at least a portion of the surface segments S. The indexing unit assigns the index N such that each indexed surface segment S can be distinguished from all other indexed surface segments S of the model M by means of its index N. This can be achieved by creating a own code or a own character combination for each surface segment S. Since each surface segment S has, for example, an area centroid on which no other area centroids are located, The index can therefore be the coordinates of the area centroid.

[0112] The confinement unit 37 is designed for creating a plurality of voxel grids G, G1 each having a plurality of voxels X, X1, wherein each voxel grid G, G1 encompasses and surrounds at least a portion of the indexed surface segment S. Thus, the surface segment is located within the voxel grid.

[0113] The processing unit 38 is designed for multiple functions, namely: determining position information L, which indicates whether the relevant voxel X, X1 is located inside or outside the contour of the model M, and assigning the position information L to the relevant voxel X, X1; and / or assigning the index N of the nearest surface segment S to the relevant voxel X, X1; and / or determining the distance A from the relevant voxel X, X1 to the surface of the model M, and assigning the corresponding distance information A to the relevant voxel X, X1.

[0114] Preferably, the modification device 34 is also designed for creating control data PS for the layer-by-layer shaped component 2 based on the modified model M. Further preferably, the modification device may be designed for determining variables based on the modified model M. Based on these variables, control data PS or additional control data PS may be output.

[0115] The modification device 34 does not have to be part of the control device 30, even if this is preferred. It can also be present externally. For example, as shown in the figure, the control device 30 can be connected to a terminal 40 with a display or the like via a bus 60 or another data connection. Via the terminal 40, an operator can control the control device 30 and thus the entire laser sintering device 1, for example by transmitting control data PS generated by the modification device 34 at the terminal (as shown by the dashed line).

[0116] At this point, it should also be noted that the present invention is not limited to such a manufacturing device 1. The present invention can be applied to other methods of generative or additive manufacturing of three-dimensional objects by layer-by-layer application and selective curing of a forming material, wherein an energy beam for curing is irradiated onto the forming material to be cured. Furthermore, correspondingly, the irradiation device can be not only a laser as described herein, but any device capable of selectively applying energy as wave or particle radiation onto or into the forming material can be used. For example, a different light source, an electron beam, etc. can be used instead of a laser.

[0117] Even in Figure 1 Only a single object 2 or component 2 is shown, but it is also possible and common to produce multiple objects in parallel in time in the processing chamber 3 or container 5. For this purpose, the energy beam 22 is scanned layer by layer in the shape material at the location corresponding to the cross section of the object in each layer.

[0118] Figure 2 A model M is shown which is shaped like a horseshoe magnet and a voxel grid G ​​which encompasses and surrounds the model M. In this example, the model M is surrounded by a bounding box B (boundary region B) from a segmentation method for the model M. The model M itself consists of surface data O, which here means surface-based image data O. Within the bounding box B, a voxel grid G ​​of voxels X is defined which has the model M inside it.

[0119] It should be noted that the bounding box B itself can constitute the volume of the voxel grid G, that is, it can be divided into the voxel grid G. If it is assumed that the bounding box B is divided into voxels X, then the illustration can be completely regarded as an example of two voxel grids G. Alternatively, the bounding box B can be regarded as a voxel grid composed of a single voxel. In other words, according to Figure 4 According to the disclosure of (see below), the bounding box can be viewed as a voxel grid (voxels) with the lowest possible resolution.

[0120] Each surface segment in the surface segments S is assigned a separate index N, where the index is represented by a "#" to represent a number. For example, the upper rectangle can be labeled 1, the side rectangles 2 and 3, the horseshoe surface 4 and 5, the inner surface 6 and 7, and the square support surface 8 and 9.

[0121] Here, a voxel X of the voxel grid G ​​is represented as a dashed cube, the distance A of the voxel being measured. This distance A is always the shortest distance A to the nearest surface segment S. Therefore, in the above example, the voxel X is assigned the index N "1".

[0122] Figure 3 A simple model M with voxels X and different position information L is shown. The model is shown in two dimensions, but it is supposed to be three-dimensional. The figure can easily be imagined as a top view of a slice. One voxel X is shown inside the model M and is labeled with the position information L "+", while one voxel X is shown outside the model M and is labeled with the position information L "-". The third voxel X is located exactly at the edge of the model and is therefore penetrated by the surface segment S. This voxel X is assigned the position information L "0".

[0123] Figure 4 Two voxel grids G, G1 of different fineness are shown, with different resolutions or different sizes of voxels X, X1. The first voxel grid G, which is coarser and larger, is shown on the top, and the finer and smaller voxel grid G1 is shown on the bottom. The dashed outline in the first voxel grid G ​​is intended to indicate that the second voxel grid G1 should be located inside the first voxel grid G ​​(see arrows). Inside the second voxel grid G1, a model M can be imagined, which is thus surrounded and enclosed by the two voxel grids G, G1.

[0124] Figure 5 The figure shows a voxel X to which different information N, L, A is assigned according to its position. Here, the dashed area should represent the interior of the model M. As shown in the figure, there are four voxels X at different positions. On the far left, there is a voxel X located inside the model M. The position information L and index N of the nearest surface segment S (shaded area) are assigned to this voxel. Since the distance of the voxel X to the surface segment S is greater than the predetermined limit value W represented by two shaded areas here, the distance information A is not assigned to the voxel X.

[0125] The distance A of the next voxel X (from left to right) to the surface segment S is smaller than a predetermined limit value W. Therefore, in addition to the position information L and the index N, distance information A is also assigned to this voxel.

[0126] The distance A of the next voxel X (from left to right) to the surface segment S is likewise smaller than the predetermined limit value W, but this voxel is outside the model M. Therefore, in addition to the position information L (here "-") and the index N, this voxel is also assigned the distance information A.

[0127] The rightmost voxel X is outside the limits. As with the leftmost voxel, only this voxel is assigned position information L and index N.

[0128] Figure 6 A two-dimensional illustration of a fine grid G1 in voxels X1 with distance information A and a coarse grid G ​​in voxels X with only index N and position information L is shown. Here, first a coarser grid G ​​can be created and information assigned to its voxels X. Then, a finer second voxel grid G1 can be created from the volume of voxels X of the coarser grid through which the surface of the model M passes (e.g., by further dividing the relevant voxels X into finer voxels X1). Then, the distance information A can also be added to it.

[0129] Figure 7 A block diagram of a method for modifying surface-based image data O of a three-dimensional geometric model M suitable for additive manufacturing of a component is shown.

[0130] On the far left are shown image data O as input data. The image data O include surface data O of a model M, which have geometric information about a plurality of surface segments S, which together form the surface of the model M. For example, the image data is an STL file of the model M, which has been previously scanned or created with the aid of a CAD program.

[0131] In step I, each surface segment S of the model M is assigned a separate index N of the image data O, so that each indexed surface segment S can be distinguished from all other indexed surface segments S of the model M by means of its index N.

[0132] In step II, a voxel grid G ​​having a plurality of voxels X is created. The voxel grid G ​​surrounds the model M and encompasses the model M, ie the model is “filled” with the voxels X of the voxel grid G.

[0133] In step III, for each voxel X of the voxel grid G, position information L is determined, which indicates whether the relevant voxel X is located inside or outside the contour of the model M and is assigned to the relevant voxel X. In addition, the index N of the nearest surface segment S is assigned to the relevant voxel X, and the distance of the relevant voxel X to the surface of the model M is also determined and assigned to the relevant voxel X.

[0134] In step IV, the model M is modified by using the voxel data to represent an implicit representation of the model M. This implicit representation is combined with another implicit surface (eg a repeating structure). This combination results in a new implicit surface representing the modified model M.

[0135] This can be achieved in particular by assigning an index N of a surface segment S to a voxel X; and performing the following steps for a plurality of points P:

[0136] - Select a point P in voxel X;

[0137] - Determine the distance of a point P from a surface segment S to which an associated index N is assigned.

[0138] In practice, the following steps are advantageous:

[0139] - check if the index N is different from the index N of the neighboring voxel, if different: determine the distance of the point P to the surface segment S assigned to the associated index N of the neighboring voxel,

[0140] - Compare the determined distances and select the smallest distance.

[0141] Then, control data PS are output based on the modified model M. Optionally, (e.g. geometric) variables may be determined based on the modified model M and control data PS may alternatively or additionally be output based on these variables. For example, contours may be extracted from the implicit surface of the modified model M or surface segments may be calculated.

[0142] Finally, it is pointed out again that the device described in detail above is only an embodiment and various modifications may be made to it by a person skilled in the art without departing from the scope of the invention. In addition, the use of the indefinite article "a" or "an" does not exclude that the relevant features may be present in plurality. Similarly, the term "unit" does not exclude that it is composed of a plurality of subcomponents that cooperate with each other and these subcomponents may also be spatially dispersed if necessary. The expression "plurality" should be understood as "at least one".

[0143] Reference numerals list

[0144] 1Device for additive manufacturing / laser sintering device

[0145] 2 Components / Objects

[0146] 3 Processing room / processing cavity

[0147] 4 Bulkhead

[0148] 5. Container

[0149] 6 container wall

[0150] 7 Work Plane

[0151] 8 Forming Field

[0152] 10 Carrier

[0153] 11 base plate

[0154] 12 Forming platform

[0155] 13 forming material (in container 5)

[0156] 14 Storage Containers

[0157] 15 Forming material (in storage container 14)

[0158] 16 Coating Machine

[0159] 17 Radiant heating device

[0160] 20 Irradiation device / irradiation device

[0161] 21 Lasers

[0162] 22 Laser beam / energy beam

[0163] 23 Deflector / Scanner

[0164] 24 Focusing device

[0165] 25 Coupling window

[0166] 29 Control Unit

[0167] 30 Control Equipment

[0168] 31 Irradiation control interface

[0169] 34 Modification Device

[0170] 35 Data Interface

[0171] 36 Index Units

[0172] 37 Restriction Unit

[0173] 38 processing units

[0174] 40 Terminal

[0175] 60 busbar

[0176] ADistance information / distance

[0177] B Limiting volume / bounding box

[0178] G, G1 voxel grid

[0179] H Horizontal direction

[0180] HS Heating Control Data

[0181] L Location Information

[0182] M Model

[0183] N Index

[0184] O Surface data

[0185] Point P

[0186] PS Process Control Data

[0187] S Surface segment

[0188] SI layer information

[0189] ST coating control data

[0190] TS Carrier Control Data

[0191] V vertical direction

[0192] W Limit

[0193] X Voxel

[0194] X1 small voxel.

Claims

1. A method for modifying surface-based image data (O) of a three-dimensional geometric model (M) suitable for additive manufacturing of a component, the image data (O) comprising surface data (O) of the model (M), the surface data having geometric information of a plurality of surface segments (S), the plurality of surface segments together forming a surface of the model (M), the method comprising the following steps: - creating a plurality of voxel grids (G, G1), each of the plurality of voxel grids having a plurality of voxels (X, X1), wherein each voxel grid (G, G1) encompasses and surrounds at least a portion of the plurality of surface segments (S), - for the plurality of voxels (X, X1) in the plurality of voxel grids (G, G1): a) determining position information (L), said position information indicating whether the relevant voxel (X, X1) is located inside or outside the contour of said model (M), and assigning said position information (X, X1) to the relevant voxel (X, X1) and / or b) assigning individual indices (N) to at least a part of the plurality of surface segments (S) of the image data (O), such that each indexed surface segment (S) can be distinguished from all other indexed surface segments (S) of the model (M) by means of its index (N), and assigning the index (N) of the nearest surface segment (S) to the relevant voxel (X, X1), and / or c) determining the distance of the relevant voxel (X, X1) from the surface of the model (M) and assigning corresponding distance information (A) to the relevant voxel (X, X1), - Outputting the plurality of voxels (X, X1) and the information (N, L, A) assigned to them.

2. A method according to claim 1, wherein voxels (X, X1) assigned the same index (N) and / or the same position information (L) are combined into groups, preferably, wherein voxels (X, X1) assigned distance information (A) are processed as individual voxels (X, X1).

3. The method according to claim 1 , wherein a plurality of voxel grids (G, G1) with different resolutions and / or different sizes are created and the voxel (X, X1) is assigned corresponding distance information (A) and / or index (N) and / or position information (L) depending on which voxel grid (G, G1) the voxel (X, X1) is located. Preferably, at least a first voxel grid (G) and a second voxel grid (G1) are defined such that the first voxel grid (G) has a coarser resolution than the second voxel grid (G1) and / or is larger than the second voxel grid (G1), wherein in the latter case, the second voxel grid (G1) is preferably located within the first voxel grid (G, G1).

4. The method according to claim 3, wherein distance information (A) is assigned only to voxels (X, X1) whose distance to the surface is less than a predetermined maximum distance, preferably, wherein the maximum distance in the first voxel grid (G) is greater than the maximum distance in the second voxel grid (G1), or in the first voxel grid (G), the voxel (X) is assigned position information (L) and / or index (N) without distance information (A), in, Preferably, each voxel (X, X1) to which a distance information (A) is assigned is also assigned at least one piece of position information (L).

5. The method according to claim 1 , wherein for determining the distance information (A) and / or the index (N) and / or the position information (L): - scanning a voxel grid (G, G1) voxel by voxel, determining and assigning a relevant value to each voxel (X, X1) in said voxel grid (G, G1), and when determining the distance, preferably determining the shortest distance to the surface of said model (M) starting from each scanned voxel (X, X1); or - scanning the model (M) surface segment by surface segment and determining, for the plurality of voxels (X, X1) surrounding the respective surface segment (S), a value associated with each voxel (X, X1) and assigning it to the associated voxel (X, X1), Preferably, within the scope of the inspection of the voxel (X, X1) to be inspected, multiple voxels (X, X1) surrounding the voxel (X, X1) are inspected to determine whether these voxels are assigned the index (N) of another surface segment (S) different from the voxel (X, X1) to be inspected. If so, the distance from the voxel (X, X1) to be inspected to the other surface segment (S) is also determined, and it is determined whether the distance is less than the distance to the initially assigned surface segment (S).

6. The method according to claim 1 , wherein a voxel (X, X1) of a voxel grid (G, G1), preferably a voxel (X, X1) in the finest voxel grid (G1), is assigned an index (N) of a surface segment (S), and wherein the following steps are performed for a plurality of points (P): - selecting a point (P) in a voxel (X, X1) of said voxel grid (G, G1); - determining the distance of said point (P) from said surface segment (S) assigned with an associated index (N), Preferably, the further steps are performed: - checking whether said index (N) is different from the index (N) of a neighbouring voxel, and if so: determining the distance of said point (P) from said surface segment (S) assigned the relevant index (N) of said neighbouring voxel, - Compare the determined distances and select the smallest distance.

7. A method according to claim 6, wherein distance information (A) is also assigned to the voxel (X, X1) in the voxel grid (G, G1), and the distance between the point (P) and the surface segment (S) is determined only when the distance of the voxel read from the distance information (A) is lower than a maximum distance, and / or wherein position information (L) is also assigned to the voxel (X, X1) in the voxel grid (G, G1), and the position information (L) is assigned to the point (P), preferably, wherein when the position information indicates the position of the voxel (X, X1) on the edge, the corresponding position information is also calculated for the point (P).

8. A method according to one of the preceding claims, wherein the output voxels (X, X1) and the information assigned to them (N, L, A) are used to create a cross-section plane of the model (M), in particular for an additive manufacturing method, preferably wherein the model (M) is a model (M) modified according to claim 7.

9. A method according to one of the preceding claims, wherein the output voxels (X, X1) and the information assigned to them are used to generate control data (PS) for a manufacturing device (1) for additively manufacturing a component (2) in a manufacturing process, in which a forming material (13) preferably comprising metal powder is formed layer by layer in a forming field (8), and correspondingly between the application of two layers of forming material (13), selective solidification of the forming material (13) is achieved by irradiating the forming material (13) with at least one energy beam (AL).

10. A modification device (34) for modifying surface-based image data (O) of a three-dimensional geometric model (M) suitable for additive manufacturing of a component (2), the image data (O) comprising surface data (O) of the model (M), the surface data having geometric information of a plurality of surface segments (S), the plurality of surface segments together forming a surface of the model (M), the modification device (34) comprising: - a data interface (35) designed to receive the image data (O), a confinement unit (37) designed to create a plurality of voxel grids (G, G1), each of which has a plurality of voxels (X, X1), wherein each voxel grid (G, G1) encompasses and surrounds at least a portion of the plurality of surface segments (S), - a processing unit (38) designed to: a) determining position information (L) indicating whether the relevant voxel (X, X1) is located inside or outside the contour of the model (M) and assigning the position information (L) to the relevant voxel (X, X1) and / or b) assigning the index (N) of the nearest surface segment (S) to the relevant voxel (X, X1), wherein the modification device (34) comprises an indexing unit (36) for this purpose, which is designed to: assign a separate index (N) to at least a part of the plurality of surface segments (S), so that each indexed surface segment (S) can be distinguished from all other indexed surface segments (S) of the model (M) by means of its index (N), and / or c) determining the distance of the relevant voxel (X, X1) from the surface of the model (M) and assigning corresponding distance information (A) to the relevant voxel (X, X1), A data interface (35) which is designed to output the voxels (X, X1) and the information (N, L, A) assigned to them.

11. A control device (30) for a manufacturing apparatus (1) for additively manufacturing a component (2) in a manufacturing process, in which a forming material (13) preferably comprising metal powder is formed layer by layer in a forming field (8), and correspondingly between the application of two layers of forming material (13), selective solidification of the forming material (13) is achieved by irradiating the forming material (13) with at least one energy beam (AL) achieved by means of an irradiation device (20), wherein: The control device (30) comprises a modification means (34) according to claim 10.

12. A manufacturing device (1) for additively manufacturing at least one component (2) in an additive manufacturing process, the manufacturing device comprising at least: - a supply device for applying a material layer of a shaping material (13) to a shaping field in the processing chamber (3); - irradiation means (20) for selectively curing by irradiation with at least one energy beam (AL) between the application of two layers of said shaping material (13); and - A control device (30) according to claim 11.

13. A data set comprising surface-based image data (O) of a model (M) and data of a plurality of voxels (X, X1) and information (N, L, A) assigned thereto, the information being created with the aid of a method according to one of claims 1 to 9, the data set in particular comprising control data (PS) for controlling a manufacturing device (1) for additive manufacturing, the control data being generated according to the method according to claim 9.

14. A manufacturing method for additively manufactured components (2), wherein a forming material (13) preferably comprising metal powder is formed layer by layer in a forming field (8), and correspondingly, between the application of two layers of the forming material (13), selective solidification of the forming material (13) is achieved by irradiating the forming material (13) with at least one energy beam (AL) based on image data (O), and the image data is modified by means of the method according to claims 1 to 9.

15. A computer program product, comprising a computer program that can be directly loaded into a storage device of a computing device, in particular a control device (30) of a manufacturing device (1) for a component layer of an additively manufactured component (2), wherein the computer program has program segments so that when the computer program is executed in the computing device, all steps of the method according to one of claims 1 to 9 are performed.

Images