3D Modeling System Extracting Feature Curves from Polygon Meshes
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Solution Overview
Problem
Existing 3D modeling techniques using polygon meshes often result in models with excessive control points, failing to accurately track curved features and sharp edges, especially for complex shapes.
Innovation Solution
A modeling system that retrieves a 3D CAD model, extracts its outer surface, identifies feature curves, generates a parameterized surface, and outputs these curves and surfaces, using a connectivity graph and spatial indexing to efficiently handle complex geometries without excessive control points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If polygon meshes are used to model objects with curved surfaces and sharp features, then the model can represent complex geometries, but the model requires an excessive number of control points that do not accurately track the curved features
Solution Approach 1:
The patent segments the 3D model into distinct feature curves (sharp edges, boundaries) and separates them from the general surface geometry. By extracting and independently representing these feature curves, the model can accurately capture sharp features without requiring excessive control points across the entire surface, thus resolving the contradiction between shape accuracy and model complexity.
Solution Approach 2:
The patent extracts feature curves from the polygon mesh surface, removing the critical geometric information (sharp edges and boundaries) from the general mesh structure. This extraction allows the remaining surface to be represented with fewer control points while the extracted feature curves preserve the accuracy of curved and sharp features, directly addressing the technical contradiction.
2Shape
If polygon meshes with excessive control points are used, then complex shapes can be represented, but processor and memory usage increase
Solution Approach 1:
By extracting feature curves from the polygon mesh, the patent separates essential geometric information from the full mesh structure. This allows the system to work with a reduced representation (feature curves + simplified surface) rather than the complete high-control-point mesh, thereby reducing processor and memory usage while preserving the ability to represent complex shapes.
Solution Approach 2:
The patent transforms the representation parameters of the 3D model by converting from a dense polygon mesh with many control points to a hybrid representation using extracted feature curves and a reduced set of surface parameters. This parameter change maintains geometric fidelity while significantly reducing computational resource requirements.
3Manufacturing precision
If polygon meshes are used for objects with sharp features, then the model can capture geometric details, but the control points do not accurately track the curved features
Solution Approach 1:
The patent extracts feature curves that specifically represent curved features and sharp edges from the polygon mesh. By isolating these critical features into separate curve representations, the system can accurately track curved features without relying on a dense distribution of control points across the entire surface, thus improving manufacturing precision while simplifying model structure.
Solution Approach 2:
The patent applies different representation qualities to different parts of the model: feature curves provide high-precision local representation for sharp edges and curved features, while the remaining surface uses a coarser parameterization. This local differentiation allows accurate tracking of curved features where needed without the overhead of excessive control points everywhere, resolving the contradiction between precision and structural complexity.
Data Source
AI summary
A modeling system is provided which retrieves from memory the 3D virtual model of an object; extract an outer surface of the 3D virtual model, the outer surface including a plurality of faces; identify feature curves in each of the plurality of faces of the outer surface; generate a parameterized surface from the identified feature curves; and output the feature curves and the parameterized surface. The system may generate a list of feature curve pairs that are adjacent to one another; obtain face pairs corresponding to the feature curve pairs; obtain and add a list of faces in the outer surface to a connectivity graph mapping points in 3D space to the feature curves; for each pair of connected faces, evaluate whether an angle difference between normals of the connected faces is greater than a threshold; and then extract a feature curve based on the pair of connected faces.