CAD (Computer-Aided Design) files may contain 2D or 3D designs. They are generated by CAD software programs, which can be used to create models or architecture plans. 2D CAD files are often referred to as drawings, while 3D files are often called models, parts, or assemblies.

 

2D files are typically used to define profiles of shapes.  Numbers, Letters, Silhouettes, Squares, Rectangles, Circles, etc.

2D files are also refered to as vector files and can be generated and exported from a variety of drawing programs.

Common 2D CAD file extensions include .DWG, .DXF, .AI, .EPS and .PDF

 

3D files are used to define three dimensional models and can contain data for surfaces or meshes.

3D files can be generated by a variety of CAD programs and also by 3D scanning an object.

Common 3D CAD files extensions that we can read are .IGS or .IGES, .STP or STEP, for surfaces and .STL or.OBJ for meshes.