Re: [PROTEL EDA USERS]: Drill Drawing

[Edi Im Hof <edi.imhof@ihe.ch>]

<x-flowed>
At 11:50 26.09.00 +0000, you wrote:
>At 01:39 AM 9/26/00 -0500, Jon Elson wrote:
>
>>Don't try to look at the .TXT file with a gerber file viewer.
>
>Technically, Mr. Elson is right. But many "gerber" viewers are really more 
>general "CAM" viewers, and will view drill files. Certainly GCPrevue does; 
>I haven't tried to use CAMtastic for this, but I would not be at all 
>surprised to find that, as Mr. Harland reports, it will read drill files.

CAMtastic does. But only the *.txt not the *.drl (the filter defaults to 
*.drl;*.dpt!). I havent investigated why drl doesnt work, because I 
generate anyway both files.

>>Although
>>these files are both variants of RS-274D (or X) syntax, the Gerber
>>files are generally created with leading zeroes suppressed and no
>>decimal points, and the drill files are generally created with TRAILING
>>zeroes suppressed, and no decimal points.  For this reason, the files
>>will massively corrupt the interpretation of coordinates.

CAMtastic can handle several gerber options:
-Zero suppression: trailing, leading, none
-Absolute, incremental
-mil, mm
-number of digits integer/decimal

I just started working with CAMtastic and I think it's worth to have a look 
at it. The most difficult thing is that the shortcut keys are COMPLETLY 
different from Protel. There is a way to change the shortcuts, havent tried.

>In both cases, gerber and drill, zero suppression, whether or not it is 
>leading or trailing is an option. I prefer to generate drill files with 
>*no* zero suppression simply because it makes the file very easy to read, 
>and drill files are typically quite small, so file size is not an issue.

I anyway zip all files togheter and a lot of zeros will compress quite 
nicely (70..80%).

>Leading zero suppression is also easy to read. With files on an inch grid, 
>assuming that the files are generated in inches, trailing zero suppression 
>can save quite a few characters, making it easier to send the files over a 
>narrow pipe.... In either case, any gerber viewer can be set for the 
>appropriate zero suppression state for each file. With a good viewer, this 
>is done automatically from information in the file header.
>
>By the way, another device for reducing gerber file size is to turn off 
>software arcs. This will permit Protel to use the gerber arc command 
>instead of drawing many individual segments. The only down side, unless 
>one is using an antique plotter, is that someone who is trying to import 
>the files into an older CAD program might find it difficult. I only 
>mention this because I used to be in that position....
>
>Centering the plots on the film can put objects off grid, and thus the 
>savings from trailing zero suppression might not exist. Centering also 
>causes the gerber to have a different reference zero than the drill files, 
>and for that reason and for others I never allow it.

Can I somewhere set the default to off for this option? This option (Centre 
on film) only works for Gerber, not for the drill files! So its useless. 
The board house will anyway position the layout on the film as they like.

Edi

>marjan@vom.com
>Abdulrahman Lomax
>P.O. Box 690
>El Verano, CA 95433



++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+  IH electronic                +  Phone:   ++41 52 320 90 00  +
+  Edi Im Hof                   +  Fax:     ++41 52 320 90 04  +
+  Doernlerstrasse 1, Sulz      +  URL:     http://www.ihe.ch  +
+  CH-8544 Rickenbach-Attikon   +  E-Mail:  edi.imhof@ihe.ch   +
+  Switzerland                  +                              +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



</x-flowed>