Constructing Regularity Feature Trees for Solid Models

Abstract

Abstract. Approximate geometric models, e.g. as created by reverse engineering, describe the approximate shape of an object, but do not record the underlying design intent. Automatically inferring geometric aspects of the design intent, represented by feature trees and geometric constraints, enhances the utility of such models for downstream tasks. One approach to design intent detection in such models is to decompose them into regularity features. Geometric regularities such as symmetries may then be sought in each regularity feature, and subsequently be combined into a global, consistent description of the model's geometric design intent. This paper describes a systematic approach for finding such regularity features based on recovering broken symmetries in the model. The output is a tree of regularity features for subsequent use in regularity detection and selection. Experimental results are given to demonstrate the operation and efficiency of the algorithm.

Symmetry Hierarchy of Man‐Made Objects

“…Earlier works such as [SV93] aim to convert boundary representations into CSG representations based on basic solid primitives. Later works try to recover feature trees and geometric constraints [LLM06]. However, the approach in these works concentrates on finding part‐level features that would enable dimension changes and construct geometric constraint graphs.…”

Discovering structural regularity in 3D geometry

“…This method is most effective for procedurally designed models where the repetitive elements appear as separate connected components. Langbein and Martin [2006] introduced regularity feature trees that provide a concise description of symmetry features in order to capture important aspects of the geometric design intent. The method is specifically designed for shapes that are bounded by planar, spherical, cylindrical, conical, and toroidal surfaces and exploits the simple geometry of these typical CAD building blocks.…”

Fast global and partial reflective symmetry analyses using boundary surfaces of mechanical components

“…Later, further work focused on identifying local approximate symmetries [20] with a complexity of O(n 4 ). Recently, the decomposition of the B-Rep model into a Regularity Feature Tree (RFT) has been combined with the detection of local approximate symmetries [21,8] as a means to connect the symmetry detection with a shape structure. This reduces the amount of symmetries being processed and produces more meaningful entities to structure a B-Rep model.…”