Editable Watertight B-Rep Conversion for Generative CAD Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Generative design solvers convert input solids to volumetric representations, leading to a loss of surface precision, particularly near sharp edges and holes, causing inaccuracies in part interferences and manufacturing defects due to the inability to accurately represent the input solid surface geometry.
Innovation Solution
A fully automatic method converts generative design into an editable, watertight boundary representation by embedding exact input solid boundary surfaces and approximating other areas with globally smooth, editable surfaces, using T-Spline or T-NURCC surfaces to reconnect the geometry, ensuring gap-free contact curves and editable surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If generative design solvers convert input solids to volumetric representations, then the geometry generation process becomes more efficient and convenient for physical simulations, but surface precision is lost particularly near sharp edges and holes
Solution Approach 1:
The patent segments the surface into two distinct parts: exact input solid boundary surfaces that are preserved with full precision, and organic surfaces that are approximated. This segmentation allows different precision requirements to be applied to different regions, maintaining manufacturing precision where needed while enabling efficient generative design elsewhere.
Solution Approach 2:
The patent applies local quality by treating different regions of the surface differently. Input solid boundary surfaces retain their exact mathematical representation for high precision requirements, while organic surfaces use approximate representations suitable for generative design efficiency. This local differentiation resolves the contradiction between precision and efficiency.
2Ease of operation
If B-Reps are sampled and replaced with volumetric representations, then the solver computations become more convenient and efficient, but the output cannot represent input solid surface geometry accurately
Solution Approach 1:
The patent introduces an intermediary conversion process that transforms the volumetric representation output from solvers back into a boundary representation format. This intermediary step reconciles the convenience of volumetric computations with the precision requirements of surface geometry representation, allowing both benefits to coexist.
Solution Approach 2:
The patent merges the exact input solid boundary surfaces with the organic surfaces generated from volumetric representations. This combination creates a hybrid model that incorporates both the computational efficiency of volumetric methods and the geometric accuracy of boundary representations.
3Ease of manufacture
If general surface reconstruction is used to create watertight B-Rep, then the model assembly can be completed, but part interferences occur due to surface inaccuracies
Solution Approach 1:
The patent performs preliminary action by preserving the exact input solid boundary surfaces before any generative design operations are applied. This pre-preservation ensures that critical geometric features maintain their accuracy throughout the design process, preventing part interferences while still enabling complete model assembly.
Data Source
AI summary
Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures include, in at least one aspect, a fully automatic method of converting a generative design into an editable, watertight B-Rep by leveraging the generative solver input and representation to: (1) embed the exact input solid boundary surfaces where the design coincides with the input, (2) approximate everywhere else the design boundary with globally smooth, editable “organic” surfaces, and (3) join all surfaces to form a generative design output B-Rep.