OpenSCAD CSG/en

Supported Elements

 * primitives: cube, sphere, cylinder, square, circle, polygon, polyhedron
 * boolean: union, difference, intersection
 * linearextrude, rotateextrude
 * import (dxf, stl, off) (without scaling or transformation of origin)
 * multmatrix
 * color

Unsupported Elements

 * projection
 * surface
 * render (ignored)
 * cgal operations: minkowski, glide, path, subdiv, hull

Supported Elements

 * primitives: Box, Cylinder, Cone, Torus
 * boolean: Cut, Fuse, Common

Fallback
Every object derived from Part::Feature which is not (yet) supported will get meshed and exported as a polyhedron element

Related

 * OpenSCAD Workbench
 * Import Export
 * FreeCAD Howto Import Export