The Programmable Computer Aided Design
Boundary representation 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.
Constructive solid geometry (CSG) connotes a family of schemes for representing rigid solids as Boolean constructions or combinations of primitives via the regularized set operations discussed above.
CSG and Boundary Representations are currently the most important representation schemes for solids.
CSG representations take the form of ordered binary trees where non-terminal nodes represent either rigid transformations (orientation preserving isometries) or regularized set operations. Terminal nodes are primitive leaves that represent closed regular sets. The semantics of CSG representations is clear. Each subtree represents a set resulting from applying the indicated transformations/regularized set operations on the set represented by the primitive leaves of the subtree.
CSG models the part as a tree structure where the leaves are positioned primitive objects and the intermediate nodes are Boolean operations to combine them.
Boundary Representation models the ‘skin’, the interface between solid and non-solid.
- Solid modeling is a consistent set of principles for mathematical and computer modeling of three-dimensional solids
- Boundary representation The history of B-rep and CAD
- Boundary representation A pdf of Solid models and B-rep
- Topology The introduction of Topology
- Euler operation The Euler operators modify the graph of connections to add or remove details of a mesh while preserving its topology.
- Euler operation The Euler operators implementation
- Euler operation The Euler operators implementation
- Euler operation The Euler operators in cgal/boost
- Constructive solid geometry In 3D computer graphics and CAD CSG is often used in procedural modeling
- NURBS
- half-edge data structure
- Open Cascade Wiki
- Open Cascade Source
- Cgal
- CGAL and the Boost Graph Library
- Parametric 2D and 3D modeler written in pure javascript
- OpenSCAD + JavaScript
- Csg on meshes using BSP trees in JavaScrip
- Verb NURBS
- Onshape Standard Library
- OpenSCAD
- FreeCAD Feature List
- FreeCAD User Hub
- FreeCAD Part Module
- FreeCAD PartDesign Module
- FreeCAD Sketcher Module
- ACIS is a geometric modeling kernel developed by Spatial Corporation (formerly Spatial Technology)