open3mod - A free, Open-Source 3D Viewer designed to make it all easier. Massive 3D Format support
LeoCAD - LeoCAD is a CAD program for creating virtual LEGO models.
MeshLab - System for processing and editing 3D triangular meshes, provides a set of tools for editing...
LDraw - LDraw is an open standard for LEGO CAD programs that allow the user to create virtual LEGO models...
noesis - Rich Whitehouse's project web site.
LDCad - LDCad is a multiplatform ...