The Gerber File format has been in use for over 30 years; during that time the Gerber Scientific company built over a dozen different machines -- first vector and later laser raster-based machines. Several of the models were very specialized (such as the VAPE machines) and only a few of these were built and used.

Over the years, the Gerber specification grew to accomodate special features of these machines as well as new functionality. Artwork's GBR_RIP software, which is designed to rasterize the Gerber data supports many but not all commands. Some unsupported commands are irrelevant -- for example those which display information on the console or those which control the velocity of the photo head.

Other commands are rarely seen because they are specific to specialized models that were built only in very small quantites.

Some commands are not supported either because we have not yet encountered their use; should the need arise support for these commands can be added. In addition to the actual commands there is often ambiguity about how to interpret or render some of the commands. Often there are interactions between commands where the documentation does not clearly state how the interaction should be handled. When in doubt we check the data against several industry standard CAM tools including CAM350 (from Downstream Technogy) and the Valor CAM station.