DTGBrepGen: A Novel B-rep Generative Model through Decoupling Topology and Geometry

CVPR 2025

1University of Science and Technology of China

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DTGBrepGen is a novel framework that sequentially generates topologically valid and geometrically high-quality B-rep models.

Abstract

Boundary representation (B-rep) of geometric models is a fundamental format in Computer-Aided Design (CAD). However, automatically generating valid and high-quality B-rep models remains challenging due to the complex interdependence between the topology and geometry of the models. Existing methods tend to prioritize geometric representation while giving insufficient attention to topological constraints, making it difficult to maintain structural validity and geometric accuracy.

In this paper, we propose DTGBrepGen, a novel topology-geometry decoupled framework for B-rep generation that explicitly addresses both aspects. Our approach first generates valid topological structures through a two-stage process that independently models edge-face and edge-vertex adjacency relationships. Subsequently, we employ Transformer-based diffusion models for sequential geometry generation, progressively generating vertex coordinates, followed by edge geometries and face geometries which are represented as B-splines.

Extensive experiments on diverse CAD datasets show that DTGBrepGen significantly outperforms existing methods in both topological validity and geometric accuracy, achieving higher validity rates and producing more diverse and realistic B-reps.

Qualitative Results

Our method generates B-rep models with enhanced structural validity and geometric fidelity, as demonstrated by the generated examples.

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Qualitative Comparison

Our method generates more realistic and geometrically precise B-rep models than baseline approaches (DeepCAD and BrepGen) on the DeepCAD dataset.

DeepCAD
DeepCAD
BrepGen
BrepGen
DTGBrepGen (ours)
DTGBrepGen (ours)

Class-Conditioned Generation

Examples of class-conditioned generation on the Furniture dataset, with distinct colors representing different categories.

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Point Cloud-Conditioned Generation

B-rep models generated based on input point clouds. Each example consists of a point cloud alongside three corresponding generated B-reps

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