A hierarchical data structure for representing assemblies: part I
Computer-Aided Design
Neighbor finding in images represented by octrees
Computer Vision, Graphics, and Image Processing
Geometric reasoning about mechanical assembly
Artificial Intelligence
Assembly features and sequence planning
GMCAD '96 Proceedings of the fifth IFIP TC5/WG5.2 international workshop on geometric modeling in computer aided design on Product modeling for computer integrated design and manufacture
Feature Modelling for Assembly
Graphics and Robotics
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This paper describes a system for the automatic recognition of assembly features and the generation of assembly/disassembly sequences. The paper starts by reviewing the nature and use of assembly features. One of the conclusions drawn from this survey is that the majority of assembly features involve sets of spatially adjacent faces. Two principle types of adjacency relationships are identified and an algorithm is presented for identifying assembly features which arise from “spatial” and “contact” face adjacency relationships (known as s-adjacency and c-adjacency respectively).The algorithm uses an octree representation of a B-rep model to support the geometric reasoning required to locate assembly features on disjoint bodies. A pointerless octree representation is generated by recursively sub-dividing the assembly model's bounding box into octants which are used to locate:Those portions of faces which are c-adjacent (i.e. they effectively touch within the tolerance of the octree).Those portions of faces which are s-adjacent to a nominated face.The resulting system can locate and partition spatially adjacent faces in a wide range of situations and a different resolutions. The assembly features located are recorded as attributes in the B-rep model and are then used to generate a disassembly sequence plan for the assembly. This sequence plan is represented by a transition state tree which incorporates knowledge of the availability of feasible gripping features.By way of illustration, the algorithm is applied to several trial components