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.
IFC or Industrial Foundation Classes is a 3D file format, used in the Architecture Engineering Construction (AEC) segment. It’s supported in the major software packages like Revit and AutoCAD by Autodesk, Tekla Structures by Tekla or SmartPlant3D by Intergraph.
The main value of the IFC is accordance to the Building Information Modeling requirements. BIM is a concept of design, construction and exploitation of the buildings prescribing creation of the large volume of the digital data around architectural objects.
This data may include not only 3D geometry, but tons of information pieces like authors, milestones and deadlines, supplier information and so on. Prior to beginning of the construction, the data base is created. It will include all the information, related to the building. Once the process kicks off the project team members will populate the data base with all the aspects of the future building.
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 more
In the 4th part of the series, we will take a look at the features of working with wireframe models in 3D CAD software.Read more