Reparametrizing Tensor Product Spline Surfaces for Gapless Continuity
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Solution Overview
Problem
Current CAD technologies face challenges in constructing gapless surface models, leading to productivity losses and increased time to market due to the need for manual repair of gaps and redundant file conversions during the conversion of models for Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), 3D printing, or additive manufacturing.
Innovation Solution
A method for constructing gapless surface models by reparametrizing tensor product spline surfaces into a common parameter space domain, ensuring that the output surfaces meet in a C0 continuous fashion along the model space trim curve, thereby eliminating gaps and allowing for immediate readiness for downstream applications like engineering analysis or manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual repair methods are used to fix gaps in CAD models, then gap remediation can be achieved, but productivity is reduced and time to market increases
Solution Approach 1:
The patent applies preliminary action by reparameterizing surfaces and computing their intersections before converting to polygonal meshes. This ensures that gaps are prevented from occurring in the first place, eliminating the need for subsequent manual repair operations and thereby maintaining both high reliability and productivity
2Adaptability or versatility
If redundant file conversion operations are performed, then model format compatibility is achieved, but time consumption increases
Solution Approach 1:
The patent performs intersection computations and gap prevention during the initial CAD model preparation stage, before any conversion operations. This preliminary handling of geometric continuity ensures that subsequent conversions to various formats (STL, VRML, etc.) can proceed directly without requiring additional gap remediation steps, thus reducing conversion time while maintaining format compatibility
3Manufacturing precision
If iterative conversion processes are used, then model accuracy can be maintained, but substantial work and time are wasted
Solution Approach 1:
The patent computes surface intersections and establishes C0 continuity in the parametric domain before mesh conversion. This preliminary geometric processing ensures that the polygonal meshes derived from reparameterized surfaces are gap-free by definition, eliminating the need for iterative accuracy checks and repairs, thus maintaining high model accuracy while significantly improving productivity
4Reliability
If designers manually repair CAD models, then model quality improves, but user frustration and dissatisfaction increase
Solution Approach 1:
The patent implements self-service by automatically computing surface intersections and generating gap-free polygonal meshes through automated reparameterization and intersection algorithms. This eliminates the need for designers to manually inspect and repair models, allowing them to directly obtain high-quality conversion results and thereby improving user satisfaction while maintaining model quality
Data Source
AI summary
A mechanism is disclosed for reconstructing trimmed surfaces whose underlying spline surfaces intersect in model space, so that the reconstructed version of each original trimmed surface is geometrically close to the original trimmed surface, and so that the boundary of each respective reconstructed version includes a model space trim curve that approximates the geometric intersection of the underlying spline surfaces. Thus, the reconstructed versions will meet in a continuous fashion along the model space curve. The mechanism may operate on already trimmed surfaces such as may be available in a boundary representation object model, or, on spline surfaces that are to be trimmed, e.g., as part of a Boolean operation in a computer-aided design system. The ability to create objects with surface-surface intersections that are free of gaps liberates a whole host of downstream industries to perform their respective applications without the burdensome labor of gap repair, and thus, multiplies the efficacy of those industries.