Create photorealistic, still, panorama, and animation image files from 3D models inside AutoCAD using raytracing and radiosity technologies. http://www.accurender.com/
Add-ons for AutoCAD and IntelliCAD for mechanical, piping, HVAC, and structural steel design [site may crash Netscape browsers] http://www.asvic.com.au/
COPRA MetalBender Software for AutoCAD, Mechanical Desktop or Inventor for parametric and non paremetric sheet metal design and unfolding. http://www.datam.de/