In solid modeling and computer-aided design, boundary representation—often abbreviated as B-rep or BREP—is a method for representing shapes using the limits. A solid is represented as a collection of connected surface elements, the boundary between solid and non-solid.
Boundary representation of models are composed of two parts: topology and geometry (surfaces, curves and points). The main topological items are: faces, edges and vertices. A face is a bounded portion of a surface; an edge is a bounded piece of a curve and a vertex lies at a point. Other elements are the shell (a set of connected faces), the loop (a circuit of edges bounding a face) and loop-edge links (also known as winged edge links or half-edges) which are used to create the edge circuits. The edges are like the edges of a table, bounding a surface portion.
Compared to the constructive solid geometry (CSG) representation, which uses only primitive objects and Boolean operations to combine them, boundary representation is more flexible and has a much richer operation set. In addition to the Boolean operations, B-rep has extrusion (or sweeping), chamfer, blending, drafting, shelling, tweaking and other operations which make use of these.
Autodesk Inventor is a program for designing three-dimensional prototypes.
Inventor uses specific file formats for parts (.IPT), assemblies (.IAM), presentations (.IPN) and drawing views (.IDW / .DWG).
A CAD file is an output of a CAD software, containing key information about the designed object: its geometry and topology representation, 3D model hierarchy, metadata, and visual attributes depending on the format of the file.
Read moreIn the 4th part of the series, we will take a look at the features of working with wireframe models in 3D CAD software.
Read moreIn the 3rd and 4th parts of the series, we will talk about surface display modes in 3D CAD programs, starting with the shading mode.
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