Although we're using EAGLE CAD from www.cadsoft.de for our PCB CAD program, we often need tools to view the output of the CAD software to verify that it's correct. We also need a program that will allow us to tile multiple Gerber files together, create one file with one aperture set, and then save as a Gerber.
Free Gerber Vierwers:
- gerbv (recommended): http://gerbv.sourceforge.net/
- GCPrevue: http://graphicode.com/
- Viewmate: http://www.lavenir.com/ (must register)