Shape Analysis by Merging Meshes With Similar Surface Normals
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Solution Overview
Problem
The analysis of object shapes from mesh data, particularly using STL data, is time-consuming due to the large number of triangular meshes required to represent the shape.
Innovation Solution
A shape analysis apparatus and method that merges triangular meshes sharing an edge and having normal vectors within a certain orientation range, reducing the number of meshes through repeated merging and analyzing the shape data based on the processed result.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mesh data uses a large number of triangular meshes to represent the object shape, then the shape representation precision is improved, but the shape analysis time is increased
Solution Approach 1:
The patent merges adjacent triangular meshes that share an edge and have normal vectors within a certain angular range. By combining multiple small triangles into larger merged meshes, the total number of meshes is reduced while preserving the essential shape characteristics. This directly addresses the contradiction by reducing mesh count (decreasing analysis time) while maintaining shape fidelity through selective merging of geometrically compatible triangles.
Solution Approach 2:
The patent applies different processing treatments to different regions of the mesh based on local geometric properties. Triangular meshes with similar orientations (normal vectors within threshold angle) are merged, while those with significantly different orientations are preserved separately. This local quality approach ensures that shape precision is maintained in regions requiring it while allowing aggregation in regions where it is acceptable, thereby optimizing the balance between precision and analysis time.
2Manufacturing precision
If the number of triangular meshes is increased to improve shape accuracy, then the manufacturing precision of the represented object is improved, but the processing complexity is increased
Solution Approach 1:
By merging adjacent triangular meshes with compatible orientations, the patent reduces the total number of mesh elements that need to be processed. This decreases the computational complexity of subsequent manufacturing operations while maintaining sufficient shape accuracy through the selective merging criterion based on normal vector alignment.
Solution Approach 2:
The patent introduces a threshold angle parameter that controls the merging criterion. By adjusting this parameter, users can balance between shape accuracy and processing complexity. A larger threshold angle allows more aggressive merging (lower complexity) while a smaller threshold angle preserves more detail (higher accuracy), providing flexible control over the trade-off between manufacturing precision and processing complexity.
Data Source
AI summary
A shape analysis apparatus includes an obtaining unit configured to obtain mesh data representing a shape of an object, using a plurality of triangular meshes; a processing unit configured to perform processing of: merging two of the plurality of triangular meshes together, the two triangular meshes sharing one edge, and a difference in orientation being within a certain range between normal vectors of the two triangular meshes; and repeatedly merging a triangular mesh included in the plurality of triangular meshes, the triangular mesh sharing one edge with the merged meshes, and a difference in orientation being within a certain range between normal vectors of the triangular mesh and the merged meshes; and an analyzing unit configured to analyze shape data representing the shape of the object, in accordance with a result of the processing performed by the processing unit.