Method, device and medium for cross-platform conversion of three-dimensional curve assets

Abstract

This application relates to the field of data mapping technology, specifically providing a method, device, and medium for cross-platform conversion of 3D curve assets, aiming to solve the problems of information loss, curvature degradation distortion, local coordinate system loss, and abnormal asset orientation caused by common intermediate formats in 3D curve assets. To this end, the method provided in this application includes: parsing the 3D curve assets of the source platform and converting the source assets into intermediate curves; performing curvature adaptive compensation on the intermediate curves to obtain a curvature-adaptively compensated curve; reconstructing the local coordinate system to obtain the optimal local coordinate system of the target platform; and performing coordinate system mapping compensation based on the original global transformation matrix, the curvature-adaptively compensated curve, and the optimal local coordinate system to obtain the 3D curve assets of the target platform. This application can avoid asset information loss, reduce curvature degradation distortion, automatically reconstruct the local coordinate system when it is lost, and reduce abnormal asset orientation.

Description

Technical Field

[0001] This application relates to the field of data mapping technology, specifically to a method, device, and medium for cross-platform conversion of 3D curve assets. Background Technology

[0002] In 3D production and simulation pipelines, 3D curve assets (including splines, Bézier curves, NURBS curves, and other mathematical structures) often need to be transferred between multiple DCC (Digital Content Creation) platforms. Different platforms have different underlying descriptions of splines, Bézier curves, NURBS curves, control points, tangents, weights, interpolation algorithms, and coordinate specifications.

[0003] Existing methods typically use a common intermediate format to transfer 3D curve assets between multiple platforms. However, importing and exporting using a common intermediate format can easily result in the loss of mathematical features of curves, such as tangents, control handles, weights, and parameter ranges. This can cause smooth curves to degenerate into broken lines or exhibit distortion in high-curvature regions. Differences in the underlying descriptions of different mathematical structures across different platforms can also cause distortion in high-curvature regions, leading to a decrease in visual fidelity. Furthermore, the conversion process using a common intermediate format often results in the loss of local coordinate system information, causing pivot point offsets, incorrect rotation axes, or a return to the world origin, which can cause downstream animation, joint motion, collision, and physics simulation logic to fail. In addition, differences in coordinate system specifications, unit scales, rotation sequences, and global transformation matrices across different platforms can cause abnormal asset orientation and pose.

[0004] Therefore, although the general intermediate format can transmit some geometric data, it will cause problems such as loss of information of 3D curve assets, curvature degradation distortion, loss of local coordinate system, and abnormal asset orientation.

[0005] Accordingly, there is a need in the field for a new cross-platform solution for converting 3D curve assets to address the aforementioned issues. Summary of the Invention

[0006] In order to overcome the above-mentioned defects, this application is made to solve or at least partially solve the technical problems of information loss, curvature degradation distortion, local coordinate system loss, and abnormal asset orientation of three-dimensional curve assets caused by the general intermediate format.

[0007] In a first aspect, a method for cross-platform conversion of 3D curve assets is provided, the method comprising:

[0008] Analyze the 3D curve assets of the source platform to obtain the set of curve geometric definition parameters, the original global transformation matrix, the original local coordinate system, and the curve type identifier;

[0009] Based on the curve type identifier and the set of curve geometric definition parameters, the 3D curve assets of the source platform are converted into intermediate curves with unified intermediate vector expression;

[0010] Perform curvature adaptive compensation on the intermediate curve to obtain the curve after curvature adaptive compensation;

[0011] Based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier, the local coordinate system is reconstructed to obtain the optimal local coordinate system of the target platform.

[0012] Based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform, coordinate system mapping compensation is performed to obtain the three-dimensional curve asset of the target platform.

[0013] In one technical solution of the aforementioned method for cross-platform conversion of 3D curve assets, the step of converting the source platform's 3D curve assets into intermediate curves with a unified intermediate vector expression based on the curve type identifier and the curve geometric definition parameter set includes:

[0014] The mapping method corresponding to the three-dimensional curve assets of the source platform is determined based on the curve type identifier;

[0015] Based on the mapping method, the set of curve geometric definition parameters is mapped to a unified parameterized expression;

[0016] Based on the unified parameterized expression, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector expression.

[0017] In one technical solution of the aforementioned method for cross-platform conversion of 3D curve assets, the unified intermediate vector representation includes curvature sampling points and curve order. The step of performing curvature adaptive compensation on the intermediate curve to obtain the curvature adaptively compensated curve includes:

[0018] Obtain the curvature sampling point density and curve order of the target platform;

[0019] The curvature sampling point density of the intermediate state curve is determined based on the curvature sampling points of the intermediate state curve.

[0020] The curvature sampling point density and curve order of the target platform are compared with the curvature sampling point density and curve order of the intermediate curve to determine the region in the intermediate curve that requires curvature adaptive compensation.

[0021] Insert control points in the region requiring adaptive curvature compensation, or adjust the weights of the control points in the region requiring adaptive curvature compensation, to obtain the modified curve;

[0022] Using the curvature sampling points of the intermediate curve as the target constraint, the modified curve is optimized based on the optimization method to obtain the curve after curvature adaptive compensation.

[0023] In one technical solution of the aforementioned method for cross-platform conversion of 3D curve assets, the step of reconstructing the local coordinate system based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier to obtain the optimal local coordinate system of the target platform includes:

[0024] When the position of the pivot point and the orientation of the XYZ axes in the original local coordinate system are available, the coordinate system specifications of the source platform and the target platform are obtained, and the coordinate axis alignment transformation is performed based on the coordinate system specifications of the source platform and the target platform to convert the original local coordinate system into the optimal local coordinate system of the target platform.

[0025] When the pivot point position and XYZ axis orientation in the original local coordinate system are unavailable, the curve after curvature adaptive compensation is analyzed to generate multiple candidate local coordinate systems and corresponding rotational joint features. The asset type is obtained based on the curve type identifier. Based on the asset type and rotational joint features, the optimal local coordinate system of the target platform is selected from the multiple candidate local coordinate systems.

[0026] In one technical solution of the above-mentioned method for cross-platform conversion of 3D curve assets, the step of performing coordinate system mapping compensation based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform to obtain the 3D curve asset of the target platform includes:

[0027] Obtain the coordinate system specifications of the source platform and the target platform;

[0028] Determine the differences between the coordinate system specifications of the source platform and the target platform, and construct a compensation matrix based on the differences;

[0029] Multiply the original global transformation matrix by the compensation matrix to obtain the global transformation matrix under the target platform coordinate system specification;

[0030] Multiply the coordinates of each control point in the curve after curvature adaptive compensation by the compensation matrix to obtain the sequence of curve control points under the target platform coordinate system specification;

[0031] The position of the pivot point and the orientation of the XYZ axes in the optimal local coordinate system are transformed by the compensation matrix to obtain the local coordinate system under the target platform coordinate system specification;

[0032] Based on the global transformation matrix, curve control point sequence, and local coordinate system of the target platform, the three-dimensional curve assets of the target platform are obtained.

[0033] In one technical solution of the above-mentioned method for cross-platform conversion of 3D curve assets, after obtaining the 3D curve assets of the target platform, the method further includes:

[0034] When the 3D curve assets of the target platform need to be used for downstream animation production or physical simulation, simulation attribute annotation is performed on the 3D curve assets of the target platform.

[0035] The simulation attributes include XYZ axes, rotation axes, motion range, collision reference, physical properties, and transformation confidence.

[0036] In one technical solution of the above-mentioned method for cross-platform conversion of 3D curve assets, after performing simulation attribute annotation on the 3D curve assets of the target platform, the method further includes:

[0037] Multiple corresponding points are sampled on the 3D curve assets of the source platform and the 3D curve assets of the target platform with the same sampling parameter values;

[0038] Calculate the Euclidean distance between each pair of corresponding points, and obtain the maximum value from multiple Euclidean distances or use the root mean square of multiple Euclidean distances as the curve sampling error;

[0039] Calculate the difference between the radii of curvature of the two curves at each pair of corresponding points, and take the maximum value from the absolute values ​​of multiple differences as the curvature error;

[0040] Calculate the Euclidean distance between the pivot point position in the original local coordinate system of the source platform and the pivot point position in the local coordinate system of the target platform, and use the Euclidean distance as the local coordinate system offset;

[0041] Calculate the first angle between the rotation axis vector in the original local coordinate system of the source platform and the rotation axis vector in the local coordinate system of the target platform, and use the first angle as the rotation consistency index;

[0042] Calculate the second angle between each axis vector in the original local coordinate system of the source platform and the corresponding axis vector in the local coordinate system of the target platform, and use the second angle as a coordinate system orientation consistency index.

[0043] In one technical solution of the above-mentioned method for cross-platform conversion of 3D curve assets, the method further includes:

[0044] When the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, and coordinate system orientation consistency index all do not exceed the preset threshold, a three-dimensional curve asset conversion report is output.

[0045] When any one of the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index exceeds a preset threshold, the 3D curve asset conversion of the source platform is determined to have failed, and the asset conversion is performed again.

[0046] in,

[0047] When the curve sampling error or the curvature error exceeds a preset threshold, the intermediate curve is re-compensated for curvature adaptive compensation.

[0048] When the local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index exceeds a preset threshold, the local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier.

[0049] In a second aspect, an electronic device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program that, when executed by the at least one processor, implements the method described in any of the above-described methods for cross-platform conversion of 3D curve assets.

[0050] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, the program codes being adapted to be loaded and run by a processor to perform the method described in any of the above-described methods for cross-platform conversion of 3D curve assets.

[0051] The above-described technical solutions of this application have at least one or more of the following beneficial effects:

[0052] In implementing the cross-platform conversion method for 3D curve assets provided in this application, the 3D curve assets of the source platform are analyzed to obtain the set of curve geometric definition parameters, the original global transformation matrix, the original local coordinate system, and the curve type identifier. Based on the curve type identifier and the set of curve geometric definition parameters, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector expression. Curvature adaptive compensation is performed on the intermediate curves to obtain curves after curvature adaptive compensation. Based on the original local coordinate system or the curves after curvature adaptive compensation and the curve type identifier, the local coordinate system is reconstructed to obtain the optimal local coordinate system of the target platform. Based on the original global transformation matrix, the curves after curvature adaptive compensation, and the optimal local coordinate system of the target platform, coordinate system mapping compensation is performed to obtain the 3D curve assets of the target platform. This application can avoid the loss of asset information, reduce curvature degradation distortion, and automatically reconstruct the local coordinate system when it is lost, while reducing abnormal asset orientation. Attached Figure Description

[0053] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Wherein:

[0054] Figure 1 This is a schematic flowchart of the main steps of a method for cross-platform conversion of 3D curve assets according to an embodiment of this application;

[0055] Figure 2 This is a schematic diagram of the main structure of an electronic device according to an embodiment of this application.

[0056] Figure label:

[0057] 11: Memory; 12: Processor. Detailed Implementation

[0058] Some embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0059] In the description of this application, "processor" can include hardware, software, or a combination of both. A processor can be a central processing unit, microprocessor, graphics processor, digital signal processor, or any other suitable processor. A processor has data and / or signal processing capabilities. A processor can be implemented in software, in hardware, or a combination of both. Computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0060] In the embodiments of this application, it should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0061] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0062] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0063] Here we will first explain some of the terms used in this application.

[0064] DCC platform: Digital content creation software platform, such as 3ds Max, Maya, Blender or equivalent 3D production software; this application aims to solve the problems encountered when transferring 3D curve assets between these different platforms.

[0065] 3D curve assets refer to 3D curve objects and their related attributes represented by different mathematical structures such as splines, Bézier curves, and NURBS curves in the DCC platform. 3D curve assets not only contain geometric shapes, but may also contain key information such as local coordinate systems used for animation and simulation.

[0066] Unified intermediate state vector representation: A data representation that does not rely on a single DCC platform, used to uniformly describe geometrically defined parameters such as control points, control handles, weights, tangents, node vectors, curvature sampling points, curve order, and parameter ranges. This unified representation preserves the mathematical information of the original curve to the greatest extent possible, laying the foundation for high-fidelity conversion.

[0067] Local coordinate system: The pivot point, orientation of the three axes (XYZ axes, i.e., X-axis, Y-axis, Z-axis) and scaling reference of the 3D curve asset itself. It usually includes the pivot point position and rotation axis direction. It is the reference reference when the 3D curve asset performs rotation, scaling and hierarchical transformation in the DCC platform. When converting between different DCC platforms, the loss or misalignment of the local coordinate system is one of the main reasons for the failure of animation and physical simulation logic.

[0068] Local coordinate system reconstruction: When the original local coordinate system is lost or reset, a reasonable local coordinate system is inferred based on geometric topology, rotation pairs, bounding boxes, and semantic features.

[0069] Coordinate system mapping compensation: global transformation matrix, curve control point sequence, and local coordinate system differences are mapped and compensated.

[0070] Coordinate system specifications refer to the coordinate system rules defined in the DCC platform, including coordinate axis orientation (e.g., Y-axis pointing upwards or Z-axis pointing upwards), unit scale, rotation order (the order of Euler angle calculation, which refers to the order of rotation around which axes, such as XYZ order, ZYX order, and ZXY order), and matrix multiplication conventions (e.g., row-major order or column-major order). Differences in coordinate system specifications between different DCC platforms are the direct cause of abnormal orientation and size after asset import.

[0071] See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a method for cross-platform conversion of 3D curve assets according to an embodiment of this application. Figure 1 As shown, the method for cross-platform conversion of 3D curve assets in this application embodiment mainly includes the following steps S101 to S105.

[0072] Step S101: Analyze the 3D curve assets of the source platform to obtain the set of curve geometric definition parameters, the original global transformation matrix, the original local coordinate system, and the curve type identifier;

[0073] Step S102: Based on the curve type identifier and the set of curve geometric definition parameters, convert the 3D curve assets of the source platform into intermediate curves with unified intermediate vector expression;

[0074] Step S103: Perform curvature adaptive compensation on the intermediate curve to obtain the curve after curvature adaptive compensation;

[0075] Step S104: Reconstruct the local coordinate system based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier to obtain the optimal local coordinate system of the target platform;

[0076] Step S105: Based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform, perform coordinate system mapping compensation to obtain the three-dimensional curve asset of the target platform.

[0077] Based on the methods described in steps S101 to S105 above, by parsing the 3D curve assets of the source platform, all mathematical and spatial information of the 3D curve assets of the source platform can be completely extracted, providing basic input data for subsequent steps; by converting the 3D curve assets of the source platform into intermediate curves with unified intermediate vector expression, the geometric definition parameters of the curves of the source assets are completely parsed and preserved, avoiding the loss of key mathematical features (such as tangents and weights) due to differences in data structures of different platforms, fundamentally ensuring the integrity of information; by performing curvature adaptive compensation on the intermediate curves, the polyline transformation and distortion in high curvature regions can be reduced, thereby reducing the degradation and distortion of the curves during the conversion process and significantly improving the visual fidelity of the final assets; by performing local coordinate system reconstruction, the original local coordinate system information can be automatically reconstructed when it is lost or unavailable, restoring the position of the axis center point and the orientation of the XYZ axes; by performing coordinate system mapping compensation, the problems of asset orientation and pose abnormalities are reduced, achieving good integration of assets in different 3D scenes.

[0078] The following describes an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application, specifically step S101.

[0079] In one embodiment of step S101 above, the three-dimensional curve assets in the source DCC platform are taken as the processing object, and the mathematical (i.e. geometric definition parameters) and spatial information (i.e. the spatial state of the three-dimensional curve assets in the source platform scene) of the source platform's three-dimensional curve assets are identified and parsed.

[0080] Specifically, the source platform type, coordinate system specification (Y-axis upward or Z-axis upward), unit scale, and curve type identifier (spline, Bézier curve, NURBS curve, etc.) are first identified. Based on this, the geometric definition parameters of the 3D curve asset and its spatial state in the source platform scene are further analyzed. The geometric definition parameters include control points, control handles, weights, node vectors, tension parameters, interpolation modes, and parameter ranges. The spatial state of the 3D curve asset in the source platform scene includes the original global transformation matrix and the original local coordinate system (i.e., the position of the axis center and the orientation of the XYZ axes).

[0081] Based on the method described in step S101 above, by parsing the 3D curve assets of the source platform, all mathematical and spatial information of the 3D curve assets of the source platform can be completely extracted, providing basic input data for subsequent steps.

[0082] The following describes an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application, specifically step S102.

[0083] In one embodiment of step S102 above, based on the curve type identifier and the set of curve geometric definition parameters, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector expression, including:

[0084] A mapping method for determining the corresponding 3D curve assets of the source platform based on curve type identifier;

[0085] Based on the mapping method, the set of geometric definition parameters of curves is mapped into a unified parameterized expression;

[0086] Based on a unified parametric representation, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector representation.

[0087] Specifically, based on the curve type identifier, the mathematical mapping method corresponding to the 3D curve assets of the source platform is selected. The set of geometrically defined parameters of the curve is then mapped to a unified parametric expression based on the selected mapping method. When the curve type identifier is a Bézier curve, the parametric expressions of the control points and control handles are obtained through Bernstein polynomial expansion. When the curve type identifier is a NURBS curve, the parametric expressions of the control points, weights, and node vectors are obtained through B-spline basis function mapping. When the curve type identifier is a spline, the tension parameters and interpolation mode are used through Hermite (Hermitian interpolation formula) or Catm... The ull-Rom interpolation method is converted into a parameterized expression of tension parameters and interpolation modes. Furthermore, it can calculate the tangent vector, curvature sampling point, and curve order at each control point, and uniformly normalize the parameter range. The parameterized expressions of control points, control handles, weights, node vectors, tension parameters, or interpolation modes, along with the tangent vector, curvature sampling point, curve order, and parameter range, constitute a unified parameterized expression. Finally, based on this unified parameterized expression, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector expression. This unified intermediate vector expression includes control point sequences, parameter ranges, weights, tangent vectors, curvature sampling points, and curve orders.

[0088] Based on the method described in step S102 above, by converting the 3D curve assets of the source platform into intermediate curves expressed by a unified intermediate vector, the geometric definition parameters of the curves of the source assets are completely parsed and preserved. This avoids the loss of key mathematical features (such as tangents and weights) due to differences in data structures between different platforms, thus fundamentally ensuring the integrity of the information. Furthermore, it avoids the problem that importing and exporting using a general intermediate format can easily result in the loss of curve mathematical features such as curve tangents, control handles, weights, and parameter ranges, leading to smooth curves degenerating into broken lines or distortion in high curvature regions.

[0089] The following describes an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application, specifically step S103.

[0090] In one embodiment of step S103 above, curvature adaptive compensation is performed on the intermediate curve to obtain a curvature adaptively compensated curve, including:

[0091] Obtain the curvature sampling point density and curve order of the target platform;

[0092] The curvature sampling point density of the intermediate state curve is determined based on the curvature sampling points of the intermediate state curve.

[0093] By comparing the curvature sampling point density and curve order of the target platform with those of the intermediate curve, the region in the intermediate curve that requires adaptive curvature compensation is determined.

[0094] Insert control points in the region where curvature adaptive compensation is needed, or adjust the weights of the control points in the region where curvature adaptive compensation is needed, to obtain the modified curve;

[0095] Using the curvature sampling points of the intermediate curve as the target constraint, the modified curve is optimized based on the optimization method to obtain the curve after curvature adaptive compensation.

[0096] Specifically, the process involves obtaining the curve types supported by the target platform and its upper limit of mathematical expression capability, including the maximum curvature sampling point density and curve order. Then, the curvature sampling point density of the intermediate curve is determined using the curvature sampling points and sampling interval of the intermediate curve. The maximum curvature sampling point density and curve order of the target platform are compared with those of the intermediate curve to determine the expression gap between them. Based on this gap, regions in the intermediate curve requiring adaptive curvature compensation are identified, typically the areas with drastic curvature changes, i.e., high curvature regions. Control points are inserted or their weights adjusted in these regions to obtain modified curves, enhancing the local expression accuracy of the area. After obtaining the modified curves, optimization methods are used to further refine them. The curvature sampling points of the interstate curve serve as the target constraint. The goal is to find the parameter combination that minimizes the fitting error (the deviation between the modified and original curvature sampling points) of the control point set in the curve. This reduces the transformation error (the external geometric deviation between the curvature-adaptively compensated curve and the source platform's 3D curve asset) in that region to within the acceptable range of the target platform. (The acceptable range for the target platform refers to the error tolerance range preset based on the target platform's curve expression capability, actual display accuracy, and simulation requirements; in other words, although the curvature-adaptively compensated curve may not be completely identical to the source platform's 3D curve asset, as long as the error is below a threshold, it is considered acceptable to the target platform.) After optimization, the curvature-adaptively compensated curve is obtained. The curvature-adaptively compensated curve includes a sequence of control points (containing the coordinates of each control point) and weights.

[0097] For example, if the curvature sampling point density of the intermediate curve in a certain region is less than that of the target platform, it indicates that the region needs curvature adaptive compensation; if the curve order of the intermediate curve in a certain region is greater than that of the target platform, it indicates that the region needs curvature adaptive compensation, and the compensation strategy is determined to be the insertion of control points; the optimization methods include least squares fitting method, piecewise interpolation method, arc length parameterization method, error backpropagation method, or adaptive resampling method.

[0098] Since the curve representation capability of the target platform may be lower than that of the source platform or intermediate state, direct conversion may lead to polyline rendering or shape distortion in high curvature regions. Based on the method described in step S103 above, curvature adaptive compensation is performed on the intermediate state curve to identify and compensate for the difference in representation capability in advance. By analyzing and enhancing the local representation accuracy of high curvature regions, polyline rendering and distortion in high curvature regions can be reduced, thereby reducing the degradation and distortion of the curve during the conversion process. This ensures the visual fidelity of high curvature regions and avoids unnecessary upgrading or densification of the entire curve, thus controlling data redundancy while ensuring quality and significantly improving the visual fidelity of the final asset.

[0099] The following describes an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application, specifically step S104.

[0100] In one embodiment of step S104 above, when the position of the pivot point and the orientation of the XYZ axes in the original local coordinate system are available, the local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier to obtain the optimal local coordinate system of the target platform, including:

[0101] Obtain the coordinate system specifications of the source and target platforms;

[0102] Based on the coordinate system specifications of the source and target platforms, coordinate axis alignment transformation is performed to convert the original local coordinate system into the optimal local coordinate system of the target platform.

[0103] Specifically, when the position of the pivot point and the orientation of the XYZ axes in the original local coordinate system are available, the coordinate axes are aligned and transformed according to the coordinate system specifications of the source platform and the target platform based on the original local coordinate system, and the original local coordinate system is re-expressed as the optimal local coordinate system that conforms to the coordinate system specifications of the target platform.

[0104] In one embodiment of step S104 above, when the position of the pivot point and the orientation of the XYZ axes in the original local coordinate system are lost or unavailable, the local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier to obtain the optimal local coordinate system of the target platform, including:

[0105] The curve after curvature adaptive compensation is analyzed to generate multiple candidate local coordinate systems and corresponding rotational pair features;

[0106] The asset type is obtained based on the curve type identifier;

[0107] Based on asset type and rotational pair characteristics;

[0108] Select the optimal local coordinate system of the target platform from multiple candidate local coordinate systems.

[0109] Specifically, when the pivot point position and XYZ axis orientation in the original local coordinate system are unavailable, a geometric topology analysis is performed on the curve after curvature adaptive compensation to identify symmetry planes, symmetry axes, cylindrical surfaces, hinge structures, bounding boxes, and key feature points. Based on this, multiple candidate local coordinate systems and corresponding rotational pair features (such as rotation axis orientation and hinge center position) are generated. The asset type (i.e., the curve is a spline, Bézier curve, NURBS curve, etc.) is obtained from the curve type identifier (spline, Bézier curve, NURBS curve, etc.) of the 3D curve asset based on the source platform. Combining the asset type and rotational pair features, the scheme that best matches the asset motion semantics from multiple candidate local coordinate systems is selected as the optimal local coordinate system of the target platform. The optimal local coordinate system includes the pivot point coordinates and XYZ axis orientation.

[0110] Local coordinate systems are crucial for animation and physics simulation, but they are easily lost during general format conversions. Misalignment of the local coordinate system can cause downstream animation, joint motion, collision, and physics simulation logic to malfunction, requiring extensive manual repair. Based on the method described in step S104 above, by reconstructing the local coordinate system, it is possible to automatically reconstruct it when the original local coordinate system information is lost or unavailable, avoiding errors in the local coordinate system and rotation axes or returning to the world origin. This prevents downstream animation, joint motion, collision, and physics simulation logic from malfunctioning, reduces manual repair, and can restore the pivot point position and XYZ axis orientation when the local coordinate system is unavailable.

[0111] The following describes an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application, specifically step S105.

[0112] In one embodiment of step S105 above, coordinate system mapping compensation is performed based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform to obtain the three-dimensional curve asset of the target platform, including:

[0113] Obtain the coordinate system specifications of the source and target platforms;

[0114] Determine the differences between the coordinate system specifications of the source platform and the target platform, and construct a compensation matrix based on these differences;

[0115] Multiply the original global transformation matrix by the compensation matrix to obtain the global transformation matrix under the target platform coordinate system specification;

[0116] Multiply the coordinates of each control point in the curve after curvature adaptive compensation with the compensation matrix to obtain the sequence of curve control points under the target platform coordinate system specification;

[0117] The position of the pivot point and the orientation of the XYZ axes in the optimal local coordinate system are transformed by the compensation matrix to obtain the local coordinate system under the target platform coordinate system specification;

[0118] Based on the global transformation matrix, curve control point sequence, and local coordinate system of the target platform coordinate system, the 3D curve assets of the target platform are obtained.

[0119] Specifically, the differences in coordinate system specifications between the source and target platforms are obtained, including coordinate axis orientation (e.g., Y-axis upward or Z-axis upward), unit scale, rotation order (the order of Euler angle calculation, referring to which axes are rotated in sequence, such as XYZ order, ZYX order, and ZXY order), and matrix multiplication convention (e.g., row-major order or column-major order). A compensation matrix is ​​constructed based on these differences. The original global transformation matrix is ​​then multiplied by the compensation matrix to obtain the global transformation matrix under the target platform coordinate system specification. The coordinates of each control point in the curve after curvature adaptive compensation are multiplied by the compensation matrix to obtain the curve control point sequence under the target platform coordinate system specification. The position of the axis center point and the orientation of the XYZ axes in the optimal local coordinate system are transformed by the compensation matrix to obtain the local coordinate system under the target platform coordinate system specification. Finally, based on the global transformation matrix, the curve control point sequence, and the local coordinate system under the target platform coordinate system specification, the 3D curve asset of the target platform is obtained.

[0120] Based on the method described in step S105 above, by performing coordinate system mapping compensation, the problems of abnormal asset orientation and posture caused by different coordinate system specifications of different platforms are reduced, and the assets are well integrated between different 3D scenes, ensuring that the assets can be presented in the correct posture and position in the target platform.

[0121] The following continues to describe an embodiment of the method for cross-platform conversion of 3D curve assets provided in this application. In one embodiment of this application, after obtaining the 3D curve assets of the target platform, the method further includes:

[0122] When the 3D curve assets of the target platform need to be used for downstream animation production or physical simulation, simulation attribute annotation is performed on the 3D curve assets of the target platform, and a structured simulation attribute description is added to the 3D curve assets of the target platform.

[0123] The simulation attributes include the XYZ axes, rotation axis (any one of the XYZ axes), motion range (parameter boundaries of curves that can be rotated or deformed), collision reference (enclosing structure description used for collision detection in the physics engine), physical attributes (simulation parameters such as mass and moment of inertia), and transformation reliability (transformation quality index evaluated by factors such as curvature compensation magnitude and local coordinate system reconstruction method).

[0124] Furthermore, after annotating the 3D curve assets of the target platform with simulation attributes, the method also includes evaluating the fidelity of this conversion:

[0125] Multiple corresponding points are sampled on the 3D curve assets of the source platform and the 3D curve assets of the target platform using the same sampling parameter values;

[0126] Calculate the Euclidean distance between each pair of corresponding points, and obtain the maximum value from multiple Euclidean distances or use the root mean square of multiple Euclidean distances as the curve sampling error;

[0127] Calculate the difference between the radii of curvature of the two curves at each pair of corresponding points, and take the maximum value from the absolute values ​​of multiple differences as the curvature error;

[0128] Calculate the Euclidean distance between the pivot point position in the original local coordinate system of the source platform and the pivot point position in the local coordinate system of the target platform, and use the Euclidean distance as the local coordinate system offset;

[0129] The first angle between the rotation axis vector in the original local coordinate system of the source platform and the rotation axis vector in the local coordinate system of the target platform is calculated, and the first angle is used as the rotation consistency index.

[0130] The second angle between each axis vector in the original local coordinate system of the source platform and the corresponding axis vector in the local coordinate system of the target platform is calculated, and the second angle is used as the coordinate system orientation consistency index.

[0131] Furthermore, when the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, and coordinate system orientation consistency index all do not exceed the preset threshold, a three-dimensional curve asset conversion report is output.

[0132] If any of the following exceeds the preset threshold: curve sampling error, curvature error, local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index, the 3D curve asset conversion of the source platform is deemed to have failed, and the asset conversion is performed again.

[0133] in,

[0134] When the curve sampling error or curvature error exceeds the preset threshold, it is determined that the 3D curve asset conversion of the source platform has failed. Curvature adaptive compensation is performed on the intermediate curve again, and asset conversion is restarted from step S103. The control point insertion, control point weight adjustment strategy or optimization algorithm fitting parameters are readjusted.

[0135] When the local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index exceeds the preset threshold, it is determined that the 3D curve asset conversion of the source platform has failed. The local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier, and the asset conversion is restarted from step S104.

[0136] Furthermore, the curve sampling error has a corresponding preset curve sampling error threshold, the curvature error has a corresponding preset curvature error threshold, the local coordinate system offset has a corresponding preset local coordinate system offset threshold, the rotation consistency index has a corresponding preset rotation consistency index threshold, and the coordinate system orientation consistency index has a corresponding preset coordinate system orientation consistency index threshold. When determining whether the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, and coordinate system orientation consistency index exceed the preset threshold, they are compared with the corresponding preset thresholds.

[0137] For example, the curve sampling error is compared with a preset curve sampling error threshold, the curvature error is compared with a preset curvature error threshold, and so on; when the curve sampling error or curvature error exceeds the preset curve sampling error threshold or the curvature error exceeds the preset curvature error threshold, the intermediate curve is re-compensated for curvature; when the local coordinate system offset exceeds the preset local coordinate system offset threshold, the rotation consistency index exceeds the preset rotation consistency index threshold, or the coordinate system orientation consistency index exceeds the preset coordinate system orientation consistency index threshold, the local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier.

[0138] Based on the above methods, by using simulation attribute annotation and assessing the success of asset conversion, the usability of converted assets in animation, joint motion, and physical simulation can be improved; manual secondary adjustments in cross-software asset transfer can be reduced, thus improving production pipeline efficiency.

[0139] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of this application, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted solutions are equivalent to the technical solutions described in this application and therefore will also fall within the protection scope of this application.

[0140] Those skilled in the art will understand that all or part of the processes in the method of the above-described embodiment can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0141] Another aspect of this application provides a computer-readable storage medium.

[0142] In one embodiment of a computer-readable storage medium according to this application, the computer-readable storage medium may be configured to store a program for performing a method for cross-platform conversion of 3D curve assets according to the above-described method embodiments. This program may be loaded and run by a processor to implement the above-described method for cross-platform conversion of 3D curve assets. For ease of explanation, only the parts related to the embodiments of this application are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of this application. The computer-readable storage medium may be a storage device comprising various electronic devices. Optionally, in the embodiments of this application, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0143] Another aspect of this application provides an electronic device.

[0144] In one embodiment of an electronic device according to this application, the electronic device may include at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program that, when executed by the at least one processor, implements the methods described in any of the above embodiments. See Appendix Figure 2 , Figure 2 The image exemplarily illustrates a communication connection between memory 11 and processor 12 via a bus.

[0145] In some embodiments of this application, the electronic device may further include at least one sensor for sensing information. The sensor is communicatively connected to any type of processor mentioned in this application. The processor communicates with the sensor to perform the methods described in any of the above embodiments. The electronic device described in this application may be, but is not limited to, mobile phones, tablets, desktop computers, laptops, handheld computers, notebook computers, ultra-mobile personal computers (UMPCs), netbooks, personal digital assistants (PDAs), etc., and this application does not limit the scope of the application.

[0146] The technical solution of this application has been described above with reference to one embodiment shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for cross-platform conversion of 3D curve assets, characterized in that, The method includes: Analyze the 3D curve assets of the source platform to obtain the set of curve geometric definition parameters, the original global transformation matrix, the original local coordinate system, and the curve type identifier; Based on the curve type identifier and the set of curve geometric definition parameters, the 3D curve assets of the source platform are converted into intermediate curves with unified intermediate vector expression; Perform curvature adaptive compensation on the intermediate curve to obtain the curve after curvature adaptive compensation; Based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier, the local coordinate system is reconstructed to obtain the optimal local coordinate system of the target platform. Based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform, coordinate system mapping compensation is performed to obtain the three-dimensional curve asset of the target platform.

2. The method according to claim 1, characterized in that, The process of converting the source platform's 3D curve assets into intermediate curves with a unified intermediate vector expression based on the curve type identifier and the set of curve geometric definition parameters includes: The mapping method corresponding to the three-dimensional curve assets of the source platform is determined based on the curve type identifier; Based on the mapping method, the set of curve geometric definition parameters is mapped to a unified parameterized expression; Based on the unified parameterized expression, the 3D curve assets of the source platform are converted into intermediate curves with a unified intermediate vector expression.

3. The method according to claim 1, characterized in that, The unified intermediate state vector representation includes curvature sampling points and curve order. The step of performing curvature adaptive compensation on the intermediate state curve to obtain the curvature adaptively compensated curve includes: Obtain the curvature sampling point density and curve order of the target platform; The curvature sampling point density of the intermediate state curve is determined based on the curvature sampling points of the intermediate state curve. The curvature sampling point density and curve order of the target platform are compared with the curvature sampling point density and curve order of the intermediate curve to determine the region in the intermediate curve that requires curvature adaptive compensation. Insert control points in the region requiring adaptive curvature compensation, or adjust the weights of the control points in the region requiring adaptive curvature compensation, to obtain the modified curve; Using the curvature sampling points of the intermediate curve as the target constraint, the modified curve is optimized based on the optimization method to obtain the curve after curvature adaptive compensation.

4. The method according to claim 1, characterized in that, The step of reconstructing the local coordinate system based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier to obtain the optimal local coordinate system of the target platform includes: When the position of the pivot point and the orientation of the XYZ axes in the original local coordinate system are available, the coordinate system specifications of the source platform and the target platform are obtained, and the coordinate axis alignment transformation is performed based on the coordinate system specifications of the source platform and the target platform to convert the original local coordinate system into the optimal local coordinate system of the target platform. When the pivot point position and XYZ axis orientation in the original local coordinate system are unavailable, the curve after curvature adaptive compensation is analyzed to generate multiple candidate local coordinate systems and corresponding rotational joint features. The asset type is obtained based on the curve type identifier. Based on the asset type and rotational joint features, the optimal local coordinate system of the target platform is selected from the multiple candidate local coordinate systems.

5. The method according to claim 1, characterized in that, The process of performing coordinate system mapping compensation based on the original global transformation matrix, the curve after curvature adaptive compensation, and the optimal local coordinate system of the target platform to obtain the three-dimensional curve asset of the target platform includes: Obtain the coordinate system specifications of the source platform and the target platform; Determine the differences between the coordinate system specifications of the source platform and the target platform, and construct a compensation matrix based on the differences; Multiply the original global transformation matrix by the compensation matrix to obtain the global transformation matrix under the target platform coordinate system specification; Multiply the coordinates of each control point in the curve after curvature adaptive compensation by the compensation matrix to obtain the sequence of curve control points under the target platform coordinate system specification; The position of the pivot point and the orientation of the XYZ axes in the optimal local coordinate system are transformed by the compensation matrix to obtain the local coordinate system under the target platform coordinate system specification; Based on the global transformation matrix, curve control point sequence, and local coordinate system of the target platform, the three-dimensional curve assets of the target platform are obtained.

6. The method according to claim 1, characterized in that, After obtaining the 3D curve assets of the target platform, the method further includes: When the 3D curve assets of the target platform need to be used for downstream animation production or physical simulation, simulation attribute annotation is performed on the 3D curve assets of the target platform. The simulation attributes include XYZ axes, rotation axes, motion range, collision reference, physical properties, and transformation confidence.

7. The method according to claim 6, characterized in that, After performing simulation attribute annotation on the 3D curve assets of the target platform, the method further includes: Multiple corresponding points are sampled on the 3D curve assets of the source platform and the 3D curve assets of the target platform with the same sampling parameter values; Calculate the Euclidean distance between each pair of corresponding points, and obtain the maximum value from multiple Euclidean distances or use the root mean square of multiple Euclidean distances as the curve sampling error; Calculate the difference between the radii of curvature of the two curves at each pair of corresponding points, and take the maximum value from the absolute values ​​of multiple differences as the curvature error; Calculate the Euclidean distance between the pivot point position in the original local coordinate system of the source platform and the pivot point position in the local coordinate system of the target platform, and use the Euclidean distance as the local coordinate system offset; Calculate the first angle between the rotation axis vector in the original local coordinate system of the source platform and the rotation axis vector in the local coordinate system of the target platform, and use the first angle as the rotation consistency index; Calculate the second angle between each axis vector in the original local coordinate system of the source platform and the corresponding axis vector in the local coordinate system of the target platform, and use the second angle as a coordinate system orientation consistency index.

8. The method according to claim 7, characterized in that, The method further includes: When the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, and coordinate system orientation consistency index all do not exceed the preset threshold, a three-dimensional curve asset conversion report is output. When any one of the curve sampling error, curvature error, local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index exceeds a preset threshold, the 3D curve asset conversion of the source platform is determined to have failed, and the asset conversion is performed again. in, When the curve sampling error or the curvature error exceeds a preset threshold, the intermediate curve is re-compensated for curvature adaptive compensation. When the local coordinate system offset, rotation consistency index, or coordinate system orientation consistency index exceeds a preset threshold, the local coordinate system is reconstructed based on the original local coordinate system or the curve after curvature adaptive compensation and the curve type identifier.

9. An electronic device, characterized in that, include: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores a computer program that, when executed by the at least one processor, implements the method for cross-platform conversion of 3D curve assets as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the method for cross-platform conversion of three-dimensional curve assets as described in any one of claims 1 to 8.

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