CAD models are usually not stored as volumetric data. Rather, such models are described by the surface(s) of the modeled objects. Commonly, those surfaces are modeled as a set of connected triangles.

ImportGeo-CAD is GeoDict’s module to read such triangulations, and to transform them into a volumetric voxel mesh.

Supported File Formats

Two file formats can be imported with ImportGeo-CAD:

• STL (STereoLithography CAD format) surface triangulation files describe only the surface geometry of a three-dimensional object without any representation of color, texture, or other attributes.

The STL format specifies both ASCII and binary representations. Binary files are more common, since they are more compact.

For more information see: https://en.wikipedia.org/wiki/STL_(file_format).

• OBJ is a geometry definition file format first developed by Wavefront Technologies for its Advanced Visualizer animation package. The file format is open and has been adopted by other 3D graphics application vendors as well.

The OBJ file format is a simple data format that represents 3D geometry alone — namely, the position of each vertex, the UV position of each texture coordinate vertex, vertex normals, and the faces that make each polygon defined as a list of vertices, and texture vertices. Vertices are stored in a counterclockwise order by default, making explicit declaration of face normals unnecessary. OBJ coordinates have no units, but OBJ files can contain scale information in a human-readable comment line.

For more information see https://en.wikipedia.org/wiki/Wavefront_.obj_file.