ISO/TS 10303-1502:2004 specifies the application module
Shell based wireframe.

The following are within the scope of
ISO/TS 10303-1502:2004:

• representation of wireframe models that are described by a graph of
  edges and vertices where the edges intersect only at their vertices;
• representation of a wireframe model by one or more shells that shall
  not overlap or intersect except at their vertices or edges;
• representation of points defined in a three-dimensional coordinate space;
• representation of curves, including b-splines, defined in a three-dimensional coordinate
  space;
• representation of a single wireframe model or an assembly of wireframe
  models.