Al, There is a company called Infinite Graphics Inc in Minneapolis MN (612-721-6283) which has a product called PAR. PAR which stands for Producibility Analysis Report is a piece of software which runs on a sun platform. Par reads in gerber data from a cad system (In our case it is Allegro by Cadence) and does various checks against your netlist. There are many manufacturing variables that may be set to check for producibility, too many to mention so call them. Many manufacturing houses are using PAR to check for manufacturing problems on incoming data. PAR is useful because depending on which type of fab house you send your boards to each house has a different level to which they can fabricate to. Give them a call, or if you want we have one person dedicated to PAR, his name is Jay Murphy and he is always willing to help. Good Luck. Mike Gnieski Senior PCB Designer EMC2 Corporation Hopkinton, MA 508-435-1000 ------------- Original Text >From [log in to unmask], on 10/20/95 11:40 AM: Design Rule Checking Kudos to the guy who first thought of, and implemented "DRC". It works very well right up to the time a designer produces gerber files. But after that, we're on our own. I understand that some Fab shops have the capability to run a DRC against the customer supplied gerber files. Sometimes spacing errors are found. But how could this be? Are cad operators not paying attention to their post-processing reports? or are they changing apertures during the gerber process? or are Fab shops changing aperture sizes and then running DRC's? I would be happy to run a DRC against my gerber files, but I have yet to see a cad system that can do it. We can simulate the artwork-select a .001 grid- and then view the simulation. But this is error prone and could make you go blind. Does software exist for a dos/unix system to run a DRC against the gerber files? I don't care about neat graphics, just a program that will allow me to check proper spacing of artwork features. Al Slagle [log in to unmask]