Open Source Solid Modeling CAD
BRL-CAD is a powerful cross-platform constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing for rendering & geometric analyses, network distributed framebuffer support, image & signal-processing tools.
UniConvertor is a universal vector graphics translator. The project uses sK1 engine to convert one format to another. It has an import filters for: CDR, CDRX, CDT, CMX, AI, CGM, WMF, XFIG, SVG, SK, SK1, AFF and export filters: AI, SVG, SK, SK1, CGM, WMF.