Watertight Boundary Representation from Generative Design Meshes
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Solution Overview
Problem
Current CAD software struggles to seamlessly integrate generative design outputs, particularly organic shapes, into watertight boundary representations, which are essential for precise manufacturing and simulation, due to limitations in handling smooth and precise mathematical surfaces.
Innovation Solution
The method involves converting polygon meshes from generative design processes into quad patch networks, using transfinite interpolation to create locally refinable smooth surface representations that fit smooth boundary curves, and stitching these surfaces with modelled solids to form a watertight 3D model, enabling precise integration with CAD models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polygon meshes from generative design are directly used, then design complexity and organic shape capability are improved, but manufacturing precision and simulation accuracy deteriorate due to discrete and approximate surfaces
Solution Approach 1:
The patent introduces an intermediary conversion process that transforms polygon meshes into watertight boundary representations. This intermediary B-Rep model serves as a bridge between the discrete mesh geometry and the precise manufacturing/simulation requirements, enabling both organic shapes and high precision without directly compromising one for the other
Solution Approach 2:
The conversion process changes the geometric representation parameters from discrete polygon vertices and faces to continuous mathematical surfaces defined by boundary curves and surfaces. This parameter transformation maintains the organic shape capability while achieving the precision required for manufacturing and simulation
2Productivity
If B-Reps are sampled and replaced with volumetric representations for generative design, then solver efficiency is improved, but integration with CAD software and manufacturing systems deteriorates
Solution Approach 1:
The patent performs preliminary conversion of the volumetric mesh output into a watertight B-Rep model before passing it to downstream CAD and manufacturing systems. This preliminary action ensures that the efficient mesh-based generative design can be seamlessly integrated with traditional CAD workflows without manual re modeling
Solution Approach 2:
The converted watertight B-Rep model serves multiple functions: it maintains the efficiency benefits of mesh-based generative design while simultaneously enabling precise CAD operations, manufacturing process planning, and simulation analysis. This universal representation bridges different manufacturing paradigms
3Adaptability or versatility
If discrete polygon mesh surfaces are used, then generative design flexibility is improved, but ease of operation in CAD programs deteriorates due to difficulty in working with mesh geometry
Solution Approach 1:
The watertight boundary representation acts as an intermediary format that preserves the flexibility of generative design outputs while making the geometry operable in traditional CAD programs. This intermediate representation enables standard CAD operations on generatively designed geometries without losing the benefits of automated design exploration
Data Source
AI summary
Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures include: obtaining a first 3D model including a polygon mesh associated with one or more modelled solids, the one or more modelled solids being in a boundary representation format; producing from the polygon mesh a quad patch network that combines, using transfinite interpolation, the polygon mesh with one or more smooth boundary curves corresponding to the one or more modelled solids; defining one or more locally refinable smooth surface representations using the quad patch network as input and based at least in part on a smallest dimension representable by a geometry modeling kernel of a computer aided design program; and combining the one or more locally refinable smooth surface representations with the one or more modelled solids to form a second 3D model that is watertight at the one or more smooth boundary curves.