Rick, If you really want to understand gerbers write a reader and read files from a couple thousand users. I did. There is so much that is not specified. Polygons are a perfect example. The use of ARC commands without re-specifying I and J parameters is another. Using the idea of "Plotting On Film" makes life simpler but the use of gerber data does not make sense for all applications. Consider a laser cutter for example. How do LGHT and DARK polygons apply when driving a laser cutter? In electronics we often use gerber files to convey electrical connectivity. Connectivity is not what gerbers were designed for but they do come "Close". Think of how difficult it might be when a given set of gerbers is given for a board design and you want to check if all GND connection make connection into a GND plane. There are various LIGHT and DARK sections in the plane as well as many pad shapes. Vaious APERTURE MACRO shapes will interact with polygons (LIGHT AND DARK), lines, flashes and feed through points (Holes). If plotting on film was all that was required gerbers would indeed be "Simpler". But using them for some other applications makes them a very poor choice. Not that there are many simpler format to select from. Bob Kondner -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Smith, Rick Sent: Thursday, March 19, 2009 4:02 PM To: [log in to unmask] Subject: Re: [TN] Gerber I vaguely remember from about a million years ago someone saying that the Gerber Scientific photoplotter format was based on the Gerber Garment fabric cutter programming. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Matthias Mansfeld Sent: Wednesday, March 18, 2009 5:40 AM To: [log in to unmask] Subject: Re: [TN] Gerber On 17 Mar 2009 at 16:41, Ahne Oosterhof wrote: > A number of weeks ago there were some questions about the Gerber > language. Those made me believe that a lot is not known about this > language. To help undo this, here is: > See also on http://en.wikipedia.org/wiki/Gerber_File looks like a rather comprehensive summary about history etc. of gerber format. The linked document at http://www.artwork.com/gerber/274x/rs274xrevd_e.pdf is also mentioned in wikipedia Best regards Matthias Mansfeld -- Matthias Mansfeld Elektronik * Leiterplattenlayout Neithardtstr. 3, 85540 Haar; Tel.: 089/4620 093-7, Fax: -8 Internet: http://www.mansfeld-elektronik.de GPG http://www.mansfeld-elektronik.de/gnupgkey/mansfeld.asc --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------