Topology (B-Rep)

B-Rep topology.

This module defines the topological entities: a body is an exact 3D geometric representation of a solid, surfacic, or wireframe model, contained in a representation item entity. For solids, a connex represents a continuous piece of material; a hollow sphere, for instance, is represented by two shells (one inner and one outer). Every shell is represented by a collection of faces sewn together; each face holds an associated geometric surface and may be trimmed by one outer loop and multiple inner loops. Currently, HOOPS Exchange does not allow a face to have multiple outer loops. Instead, you can make several faces, each containing a single outer loop. A loop is a collection of oriented and ordered co-edges, containing space parametric curves (if any), and neighboring information; each co-edge holds an edge, which in turn holds 3D information such as 3D curves and vertices. The current API handles only manifold solids, which have single neighbors per co-edge.

An A3DTopoContext defines a global tolerance for every topological entity in this context. This global tolerance can then be superseded by less strict local tolerances for particular entities such as edges.

Tolerance

In general, if the local tolerance is lower than the tolerance specified in the associated A3DTopoContext entity, you must use the tolerance from the A3DTopoContext entity.

Topics