3D Model Parametric Patches for Subdivision Surface Design
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Solution Overview
Problem
Existing solutions for designing 3D modeled objects using subdivision surfaces face inefficiencies in creating satisfactory character lines and transition zones, requiring manual adjustments and rework when the initial surface is modified, as these processes are not captured by CAD systems for automatic replay.
Innovation Solution
A computer-implemented method that converts faces of a base mesh into parametric patches with specific connection attributes across a polyline, allowing for the creation of character lines and transition zones in a fast, flexible, and robust manner by defining smooth and sharp portions of the polyline and applying G0 and Gi connections to adjacent patches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual adjustments are made to create character lines and transition zones on subdivision surfaces, then design flexibility is improved, but design time and productivity deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-defining the transition zone specification at the base mesh level before surface generation. The system identifies and marks the transition zone on the base mesh, so that when the subdivision surface is generated or modified, the transition zone is automatically created or updated without requiring manual intervention. This resolves the contradiction by automating what was previously a manual process, thereby improving productivity while maintaining design flexibility.
2Manufacturing precision
If transition zones are recreated manually when the base mesh is modified, then design accuracy is maintained, but design efficiency deteriorates
Solution Approach 1:
The patent implements feedback by establishing an associative link between the base mesh and the transition zone specification. When the base mesh is modified, the system automatically detects the change and updates the transition zone accordingly, ensuring that the transition zone remains consistent with the current mesh geometry. This feedback mechanism maintains design accuracy while eliminating the need for manual recreation, thereby improving design efficiency.
3Manufacturing precision
If the subdivision surface is refined to improve character line quality, then surface precision is improved, but computational complexity and processing time deteriorate
Solution Approach 1:
The patent applies local quality by focusing computational resources only on the transition zone areas rather than uniformly refining the entire surface. The system identifies specific regions where transition zones are needed and applies refinement only to those local areas, maintaining surface precision where required while avoiding unnecessary computational complexity in other regions. This selective approach resolves the contradiction between precision and computational complexity.
Data Source
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AI summary
It is provided a computer-implemented method for designing a 3D modeled object. The method comprises providing (S10) a base mesh controlling a subdivision surface. The subdivision surface models the 3D modeled object. The method also comprises providing (S20) a polyline consisting of connected edges of the base mesh and defining (S30) a smooth portion of the polyline comprising an extremity of the polyline and a sharp portion of the polyline upstream the smooth portion. The method also comprises converting (S40) faces of the mesh adjacent to the polyline into parametric patches approximating the subdivision surface. The patches have a G0 connection across the sharp portion of the polyline, and the patches have a Gi connection across the smooth portion of the polyline, where i is an integer higher or equal to 1. Such a method improves the design of a 3D modeled object modeled by a subdivision surface.