LOD layered generation method, system, and storage medium based on component semantic segmentation

Abstract

The present invention relates to building information model visualization technology, specifically a LOD layered generation method, system, and storage medium based on component semantic segmentation. The method comprises: obtaining model components and their component categories; setting the semantics of the component categories according to semantic specifications, and dividing the model components according to the semantics of the component categories; pre-processing the model components, deleting closed space components and split surface components under the component categories, and ungrouping the model groups; segmenting the BIM model based on the semantics of the component categories to generate multiple LOD levels, including a first LOD level, a second LOD level, a third LOD level, and a fourth LOD level; and processing component textures so that the first LOD level and the second LOD level do not display texture attributes. The present invention solves the problem that existing LOD layered results do not contain semantics and do not meet business display requirements, and cannot adapt to the level of detail required for model display content in different environments.

Description

Technical Field

[0001] The present invention relates to a building information model visualization technology, in particular to a LOD layered generation method, system and storage medium based on component semantic segmentation. Background Art

[0002] Existing BIM LOD technology determines the resource allocation for object rendering based on the position and importance of the object model's nodes in the display environment. It has the following limitations: The current LOD is mainly based on algorithmic stratification, which causes the same object to be divided and dispersed into different layers, with each layer containing different parts of the object. Because the layered results do not contain semantics, they are not conducive to the actual application of the model, do not meet business display needs, and cannot adapt to the different levels of detail required for model display content in different projects and applications; they require the collaboration of multiple software programs, making the operation cumbersome and complex; they lack texture mapping processing; and they lack support for practical applications and business presentations. Summary of the Invention

[0003] In order to overcome the defects of the existing technology, the present invention provides an LOD layered generation method, system, and storage medium based on component semantic segmentation, and performs LOD layered display based on component semantic segmentation to make up for the shortcomings of LOD layering based on algorithm segmentation, and solve the problem that the existing LOD layering results do not contain semantics and do not meet business display requirements, and cannot adapt to the level of refinement of model display content in different environments.

[0004] The LOD layered generation method in one embodiment of the present invention is implemented using the following technical solution: The LOD layered generation method based on component semantic segmentation includes the following steps:

[0005] Read the BIM model source file to obtain the components of the BIM model and the component category and component attribute information of each component;

[0006] Set the semantics of component categories according to semantic specifications, and divide BIM model components according to the semantics of component categories;

[0007] Pre-process BIM model components, delete closed space components and split surface components under the component category, ungroup model groups composed of multiple components in the component category, decompose parts composed of multiple different types of components in the component category, and delete links and annotations in the component category;

[0008] Based on the semantics of component categories, the BIM model is segmented and multiple LOD levels are generated according to the different requirements of different projects and applications for the level of detail of model display content. The multiple LOD levels include the first LOD level, the second LOD level, the third LOD level, and the fourth LOD level.

[0009] Process component textures so that the first and second LOD levels do not display texture attributes.

[0010] The LOD layered generation system in one embodiment of the present invention is implemented using the following technical solution: The LOD layered generation system based on component semantic segmentation includes:

[0011] A file reading module is used to obtain the components of the BIM model and the component category and component attribute information of each component;

[0012] The semantic setting module is used to set the semantics of component categories according to semantic specifications and divide BIM model components according to the semantics of component categories;

[0013] The component preprocessing module preprocesses BIM model components, deletes closed space components and split surface components under the component category, ungroups model groups composed of multiple components in the component category, decomposes parts composed of multiple different types of components in the component category, and deletes links and annotations in the component category;

[0014] The segmentation module segments the BIM model based on the semantics of component categories and the different levels of detail required for model display content in different projects and applications, generating multiple LOD levels; the multiple LOD levels include the first LOD level, the second LOD level, the third LOD level, and the fourth LOD level;

[0015] The component texture processing module processes the component textures of the first LOD level and the second LOD level segmentation results so that the first LOD level and the second LOD level do not display texture attributes.

[0016] The storage medium in one embodiment of the present invention stores computer instructions thereon, and when the computer instructions are executed by a processor, the steps of the LOD layered generation method based on component semantic segmentation of the present invention are implemented.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] 1. The present invention solves the problem that LOD layered results do not contain semantics, enabling LOD to segment models based on semantics. The layered result file is an object containing component semantics, which meets business display needs and adapts to the different levels of detail required for model display content in different projects and applications. It does not require the collaboration of multiple software, simplifies the environment installation and operation process, realizes one-click operation, and automatically extracts, thereby improving work efficiency.

[0019] 2. The present invention defines semantic specifications and the types of objects displayed at different levels according to the requirements of different projects and applications for different levels of refinement of model display content; the model is layered according to the semantics corresponding to the objects to achieve semantic LOD layering.

[0020] 3. The present invention optimizes the processing of object texture mapping, simulating the different contents that users can see at different distances from objects; and saves the result file in a format commonly used in the industry, achieving lightweight 3D data, instant transmission, and efficient analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a flow chart of a LOD layered generation method according to an embodiment of the present invention;

[0022] Figure 2 It is a structural block diagram of the LOD layered generation system in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0024] Example 1

[0025] like Figure 1 As shown, this embodiment provides a LOD layered generation method based on component semantic segmentation, comprising the following steps:

[0026] S1. Read the BIM model source file to obtain the components of the BIM model and the component category and component attribute information of each component.

[0027] Read the BIM model source file, obtain all the components of the BIM model through the component collection (Filtered Element Collector), and obtain the component category and component attribute information of each component. The obtained component category is the basis for subsequent component semantic segmentation.

[0028] S2. Set the semantics of component categories according to semantic specifications, and divide BIM model components according to the semantics of component categories.

[0029] The BIM model components are divided according to the semantics of the component category. As shown in Table 1, the BIM model components are divided into multiple component categories, such as OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, OST_Columns, OST_PipeFitting, OST_Railing, OST_Beam, OST_Stairs, OST_Furniture, OST_PlumbingFixtures, OST_Rooms, OST_ElectricalEquipment, and OST_FaceSplitter. Each component category can have its own basic properties such as name and texture. Each component category also has its own special properties. For example, OST_Rooms is composed of multiple walls, and OST_IOSModelGroups is composed of multiple components.

[0030] Table 1

[0031]

[0032]

[0033] S3. Preprocessing of BIM model components

[0034] S31. Processing the topological relationship between closed spaces and walls

[0035] The OST_Rooms component class semantics refers to a closed space enclosed by multiple walls, including living rooms, kitchens, bathrooms, bedrooms, etc. The OST_Rooms component class prevents the walls that make up this closed space from being removed.

[0036] Therefore, this step needs to find out the components whose component attribute information is closed space and delete the closed space components; specifically: traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_Rooms. If so, delete the closed space, and finally delete all closed components such as living rooms, kitchens, bathrooms, bedrooms, etc. of the OST_Rooms category in the BIM model.

[0037] S32. Processing the relationship between split surfaces and textures

[0038] The semantics of the OST_FaceSplitter component class refers to face splitting. Face splitting can divide a complete floor slab into different areas, each of which can be assigned a different texture. The texture of a floor slab divided by a face splitting cannot be modified.

[0039] Therefore, this step needs to find the floor slabs containing split faces and delete the split faces; specifically: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_FaceSplitter, and if so, delete the split face, and finally delete all split faces of the OST_FaceSplitter category in the BIM model.

[0040] S33. Ungroup the model group

[0041] The semantics of the OST_IOSModelGroups component category refers to a model group consisting of multiple components. Components within a model group can be modified, moved, loaded, and so on in a unified manner. Only after the model group is ungrouped can the components within it be modified and take effect. Otherwise, the components within the group will not take effect after the modification.

[0042] Traverse the components in the model, obtain the component category, and determine whether it belongs to OST_IOSModelGroups. If so, use UngroupMembers to ungroup it, and finally ungroup all model groups of the OST_IOSModelGroups category in the model.

[0043] S34. Decompose the components

[0044] The semantics of the OST_Assemblies component class refers to an assembly composed of multiple components of different types. Assemblies can be planned, labeled, and isolated. When an assembly is not decomposed, the components within it cannot be modified.

[0045] Traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_Assemblies. If so, use Disassemble to decompose it, and finally decompose all the components of the OST_Assemblies category in the model.

[0046] S35, Link

[0047] The semantics of the OST_RvtLinks component class refers to the association between the current model and an external model. Links allow you to reference and use components in external models. When a link exists, you can modify components within the model, but the changes will not take effect.

[0048] Traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_RvtLinks. If so, use modelDocument.Delete(links) to delete the link.

[0049] S36, annotation

[0050] The semantics of the OST_Dimensions component class refers to scale or dimension annotations in the model, which are used to annotate the size, scale, spatial usage, etc. of the model drawings. If annotations exist, the components associated with the annotations cannot be modified.

[0051] Traverse the components in the model, get the component category, and determine whether it belongs to OST_Dimensions. If so, use modelDocument.Delete(dimensions) to delete the annotation.

[0052] S4. Based on the semantics of component categories, segment the BIM model and generate multiple LOD levels.

[0053] In this step, the LOD levels are divided according to the different levels of detail required for model display content in different projects and applications. The first LOD level has a lower level of detail, retaining only the model's external components and not displaying its texture attributes. Specifically, the retained component categories include: OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, and OST_Columns, as shown in Table 2.

[0054] Table 2

[0055] Constructing the semantics of categories Chinese meaning OST_Walls wall OST_Doors Door OST_Windows window OST_Floors floor OST_Roofs roof OST_Columns column

[0056] When generating the first LOD level, the components in the BIM model are traversed to obtain the category attribute of the component. The BuiltInCategory value in the category attribute is the semantics of the component category. The generation process of the first LOD level includes the following steps:

[0057] Traverse the components in the BIM model and determine whether the semantics of the component category is one of OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, and OST_Columns. If so, retain the component; otherwise, do not retain the component.

[0058] After traversing all components in the BIM model, only the component categories with the semantics of OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, and OST_Columns are retained, and then the result file is saved, completing the first semantic segmentation of the model and obtaining the segmentation results of the first LOD level.

[0059] The second LOD level is also less detailed, and the components retained are those outside the model: specifically, roof decorations and pipes, and the texture properties of this layer are not displayed.

[0060] The third level of detail increases the level of detail of the first and second levels. It includes the component categories of the first and second levels, and also adds the component categories of OST_Railing, OST_Beam, OST_Stairs, and OST_Furniture. The third level of detail displays the texture properties of all components, achieving a higher level of detail.

[0061] The fourth LOD level retains all components in the model except the third LOD level. Components at this level are smaller and more detailed than those at the third LOD level. This layer also displays the texture properties of all components, achieving a further improvement in refinement.

[0062] The semantics of component categories retained from the second LOD level to the fourth LOD level are shown in Table 3 below:

[0063] Table 3

[0064]

[0065] Similarly, according to the semantics defined in Table 3, the BIM model is semantically segmented for the second, third, and fourth times to form the segmentation results of the second LOD level, the third LOD level, and the fourth LOD level.

[0066] S5. Processing component texture

[0067] Generally, components have texture attributes. The first and second LOD levels do not need to display the specific texture of the component, so the component textures of the first and second LOD level segmentation results need to be processed. Different types of components have different texture attribute processing methods, so the method of modifying component textures is also different. In this embodiment, the texture acquisition and modification methods are divided into the following four cases:

[0068] "Wall" type component:

[0069] This type of component includes walls, floors, curtain walls, roofs, etc., and its texture is set in the CompoundStructure property. Traverse the components in the BIM model, obtain the component's compound properties, and modify the component's texture property to a null value using the SetCompoundStructure method to achieve the effect of not displaying the texture property at the first and second LOD levels.

[0070] "Door" type component:

[0071] This type of component includes handles, window frames, and other items, whose textures are set in the ParameterSet. Traverse the components in the BIM model, obtain the component and the PG_MATERIALS properties in the ParameterSet, and use the Parameter.Set method to modify the component's texture properties to null values, thus preventing the display of texture properties at the first and second LOD levels.

[0072] Pipe type components:

[0073] This type of component is primarily pipes, fittings, elbows, etc., and its texture is set in the component's MEPSystem (piping system). Traverse the components in the BIM model, obtain the component's MEPSystem (piping system) information and ParameterSet (parameter set) information, and modify the component's texture properties to null values ​​using the Parameter.Set() method, achieving the effect of not displaying texture properties at the first and second LOD levels.

[0074] "Split Face" type component:

[0075] Splitting faces is primarily used to divide a component into distinct regions, each of which can be assigned a different texture. Textures are set in the GeometryElement properties. By traversing the components in the BIM model, obtaining the component's GeometryElement and Faces properties, and then using the Paint method to modify the component's texture properties to null, this will prevent the texture properties from being displayed at the first and second LOD levels.

[0076] S6. Save the result file

[0077] The results of the first LOD level and the second LOD level after texture processing in step S5 and the third LOD level and the fourth LOD level after segmentation in step S4 are saved for use in other applications or business scenarios.

[0078] Example 2

[0079] Based on the same inventive concept as Example 1, this embodiment provides a LOD layered generation system based on component semantic segmentation, including:

[0080] The file reading module is used to obtain the components of the BIM model and the component category and component attribute information of each component. After reading the BIM model source file, it obtains all the components of the BIM model through the component collection (Filtered Element Collector) and obtains the component category and component attribute information of each component. The obtained component category is the basis for subsequent component semantic segmentation.

[0081] The semantic setting module is used to set the semantics of component categories according to semantic specifications and divide BIM model components according to the semantics of component categories. The divided component categories include OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, OST_Columns, OST_PipeFitting, OST_Railing, OST_Beam, OST_Stairs, OST_Furniture, OST_PlumbingFixtures, OST_Rooms, OST_ElectricalEquipment and OST_FaceSplitter;

[0082] The component preprocessing module preprocesses BIM model components, including processing the topological relationship between closed spaces and walls, processing the relationship between split surfaces and textures, ungrouping model groups, decomposing components, and deleting links and annotations.

[0083] The Segmentation module segments the BIM model based on the semantics of component categories, generating multiple Level of Detail (LOD) levels. The LOD levels are divided based on the varying levels of detail required for model display by different projects and applications. The first LOD level maintains only the model's external components and does not display texture properties. Component categories retained at this level include: OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, and OST_Columns. The second LOD level also maintains lower detail, retaining external components such as roof decorations and pipes, and also does not display texture properties. The third LOD level builds upon the first and second LOD levels, encompassing the component categories of the first and second LOD levels and adding the component categories OST_Railing, OST_Beam, OST_Stairs, and OST_Furniture. Texture properties for all components are displayed at this level, achieving increased detail. The fourth LOD level refers to the components in the model other than the third LOD level. Components at this level are smaller and more detailed than those at the third LOD level. This layer also displays the texture properties of all components, achieving a further improvement in refinement.

[0084] A component texture processing module processes the component textures of the first LOD level and the second LOD level segmentation results so that the first LOD level and the second LOD level do not display texture attributes;

[0085] The saving module is used to save the result file, including the first LOD level and the second LOD level processed by the component texture processing module, and the third LOD level and the fourth LOD level segmented by the segmentation module.

[0086] Among them, the component preprocessing module performs various preprocessing on the components, specifically:

[0087] Process the topological relationship between closed spaces and walls: traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_Rooms. If so, delete the closed space. Finally, delete all closed components such as living rooms, kitchens, bathrooms, and bedrooms in the BIM model that belong to the OST_Rooms category.

[0088] Handle the relationship between split faces and textures: traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_FaceSplitter. If so, delete the split face, and finally delete all split faces of the OST_FaceSplitter category in the BIM model;

[0089] Ungroup the model group: traverse the components in the model, obtain the component category, and determine whether it belongs to OST_IOSModelGroups. If so, use UngroupMembers to ungroup it, and finally ungroup all model groups of the OST_IOSModelGroups category in the model;

[0090] Decompose the components: traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_Assemblies. If so, use Disassemble to decompose it, and finally decompose all the components of the OST_Assemblies category in the model;

[0091] Delete links: traverse the components in the BIM model, obtain the component category, and determine whether it belongs to OST_RvtLinks. If so, use modelDocument.Delete(links) to delete the link;

[0092] Delete annotations: traverse the components in the model, obtain the component category, and determine whether it belongs to OST_Dimensions. If so, use modelDocument.Delete(dimensions) to delete the annotations.

[0093] This embodiment also provides a storage medium based on the same inventive concept as that of embodiment 1, on which computer instructions are stored. When the computer instructions are executed by a processor, the various steps of the LOD hierarchical generation method based on component semantic segmentation in the above embodiment 1 are implemented.

[0094] Since the BIM model does not have high requirements for the content and details required for the model in the early application stage of the project life cycle, the highly complex BIM model brings a burden to the engineering application. Therefore, the present invention automatically extracts LODs of different levels of the BIM model to adapt to the requirements of different projects and applications for model accuracy, which is the key to the large-scale application of BIM. The present invention performs LOD layered display through component semantic segmentation, which makes up for the shortcomings of the existing algorithm-based LOD layering and solves the problem that the LOD layering results do not contain semantics. It enables LOD to segment the model based on semantics. The result file contains objects with semantics, which meets the business display needs and adapts to the different levels of refinement of model display content required by different projects and applications. Based on the different stages of engineering application, the BIM model is divided according to semantic understanding to achieve automatic extraction of LODs of different levels of the BIM model, thereby accelerating the drawing of the scene and improving the responsiveness of the system.

[0095] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A LOD layered generation method based on component semantic segmentation, characterized in that: The following steps are involved: Read the BIM model source file to obtain the components of the BIM model and the component category and component attribute information of each component; Set the semantics of component categories according to semantic specifications, and divide BIM model components according to the semantics of component categories; Pre-process BIM model components, delete closed space components and split surface components under the component category, ungroup model groups composed of multiple components in the component category, decompose parts composed of multiple different types of components in the component category, and delete links and annotations in the component category; Based on the semantics of component categories, the BIM model is segmented and multiple LOD levels are generated according to the different requirements of different projects and applications for the level of detail of model display content. The multiple LOD levels include a first LOD level, a second LOD level, a third LOD level, and a fourth LOD level; Process component textures so that the first and second LOD levels do not display texture attributes; According to the semantic specification, the semantics of component categories are set, and the BIM model components are divided into multiple component categories, including OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, OST_Columns, OST_PipeFitting, OST_Railing, OST_Beam, OST_Stairs, OST_Furniture, OST_PlumbingFixtures, OST_Rooms, OST_ElectricalEquipment and OST_FaceSplitter. Each component category has basic attributes and special attributes, among which the basic attributes include the name and texture attributes of the component category itself; The process of deleting closed space components under the component category is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_Rooms, and if so, delete the closed space surrounded by multiple walls under the OST_Rooms component category. The closed space includes the living room, kitchen, bathroom and bedroom. The process of deleting split face components is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_FaceSplitter, and if so, delete the split face under the OST_FaceSplitter component category; The ungrouping process is as follows: traverse the components in the model, obtain the component category, determine whether it belongs to OST_IOSModelGroups, and if so, perform ungrouping; The decomposition process is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_Assemblies, and if so, perform decomposition.

2. The LOD layered generation method according to claim 1, wherein: When reading a BIM model file, all components of the BIM model are obtained through the component collection, and the component category and component attribute information of each component are obtained.

3. The LOD layered generation method according to claim 1, wherein: The first LOD level only retains the external components of the model and does not display the texture properties of this layer. The retained component categories include: OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, and OST_Columns; In the second LOD level, the external components of the model, including roof decoration and pipes, are retained, and the texture properties of this layer are not displayed; The third LOD level improves the level of detail based on the first and second LOD levels, and displays the texture properties of all components. It includes the component categories of the first and second LOD levels, and adds the component categories of OST_Railing, OST_Beam, OST_Stairs, and OST_Furniture. The fourth LOD level retains all components in the model except the third LOD level and displays the texture properties of all components.

4. The LOD layered generation method according to claim 1, wherein: When processing component textures, for "wall" type components, obtain and set the component's composite properties, and modify the component texture properties to null values ​​by setting the composite properties; for "door" type components, obtain the material type properties in the parameter set of this type of component, and modify the component texture properties to null values ​​by setting the parameters; for "pipe" type components, obtain the piping system information and parameter set information of this type of component, and modify the component texture properties to null values ​​by setting the parameters; for "split surface" type components that divide the complete component into different areas, obtain the geometric elements and surface properties of this type of component, and modify the component texture properties to null values ​​by using the painting method.

5. A LOD layered generation system based on component semantic segmentation, characterized in that: include: A file reading module is used to obtain the components of the BIM model and the component category and component attribute information of each component; The semantic setting module is used to set the semantics of component categories according to semantic specifications and divide BIM model components according to the semantics of component categories; The component preprocessing module preprocesses BIM model components, deletes closed space components and split surface components under the component category, ungroups model groups composed of multiple components in the component category, decomposes parts composed of multiple different types of components in the component category, and deletes links and annotations in the component category; The segmentation module segments the BIM model based on the semantics of component categories and generates multiple LOD levels according to the different requirements of different projects and applications for the level of detail of model display content; The multiple LOD levels include a first LOD level, a second LOD level, a third LOD level, and a fourth LOD level; A component texture processing module processes the component textures of the first LOD level and the second LOD level segmentation results so that the first LOD level and the second LOD level do not display texture attributes; The semantic setting module sets the semantics of component categories according to semantic specifications, and divides BIM model components into multiple component categories such as OST_Walls, OST_Doors, OST_Windows, OST_Floors, OST_Roofs, OST_Columns, OST_PipeFitting, OST_Railing, OST_Beam, OST_Stairs, OST_Furniture, OST_PlumbingFixtures, OST_Rooms, OST_ElectricalEquipment and OST_FaceSplitter. Each component category has basic attributes and special attributes, among which the basic attributes include the name and texture attributes of the component category itself; The component preprocessing module performs various preprocessing on components: The process of deleting closed space components under the component category is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_Rooms, and if so, delete the closed space surrounded by multiple walls under the OST_Rooms component category. The closed space includes the living room, kitchen, bathroom and bedroom. The process of deleting split face components is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_FaceSplitter, and if so, delete the split face under the OST_FaceSplitter component category; The ungrouping process is as follows: traverse the components in the model, obtain the component category, determine whether it belongs to OST_IOSModelGroups, and if so, perform ungrouping; The decomposition process is as follows: traverse the components in the BIM model, obtain the component category, determine whether it belongs to OST_Assemblies, and if so, perform decomposition.

6. A storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the steps of the LOD hierarchical generation method based on component semantic segmentation according to any one of claims 1 to 4 are implemented.

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