Re: Circuit Board Layout Program

Hi Jon,

Yes, I can see where a raster bitmap would be an entirely different sort
of algorithm then what I am attempting. Interesting, but different. I
wasn't planning on arcs, although they might not be too bad. Building a
netlist is an interesting problem to solve, but as you've observed, it
can get fooled rather easily. My first rub was closed loop traces. A
"visited" flag solved that. A big pileup of pads or traces (like for a
heatsink) still fails. I'm not anxious to fix that. But in general, if
I can stay away from such stuff, like "starburst" heatsinks, and
multiple trace buildups, it's useable.

I haven't done anything yet with the Excellon drill files, probably not
hard to do. My code is in 'C', and the user interface is a series of
objects, giving me menu driven programs. I'm always surprised how much
Pascal is still around. I had just started to use it when the 'C'
compiler came out for PC's, first Lifeboat, then after Microsoft bought
them out, Microsoft compilers.

The fractals are quite interesting. I'll have to check them out.
Programs you say?

Alan KM6VV

Jon Elson wrote:

>
> Alan Marconett KM6VV wrote:
>
> >
> > Thanks for the comments. Any other thoughts on converting Gerber files?
> >
>
> Well, I wrote a 20,000 line or so program that reads Gerber (RS-274D)
> files with most features supported (It still doesn't do arcs, similar to a
> G02 or G03) and creates a raster bitmap to drive my photoplotter.
> It is in Pascal, and is fairly specialized for raster creation, rather than
> putting a netlist back together, which is what you are pretty much doing.
>
> Some cad software will make multiple stripes of smaller apertures to
> build up the 'pen' width to make a track that is not supported by an
> aperture. This could drive your software nuts. (And, it might drive
> YOU nuts trying to figure out an algorithm that can handle that special
> case.)
>
> I have also done a little bit of work in this general area, such as converting
> Excellon drill files (which look a LOT like the Gerber dialect of RS-274D)
> to pure, industry-standard "G-code", and then drilling my boards on
> my mill. I have programs, again in Pascal, to convert Excellon files
> to Allen-Bradley 7320-style G-code (mostly no decimal point) and
> to EMC-style G-code.
>
> I also have a couple little programs that will output fractal figures in
> either Gerber format or G-code for engraving the lines. See
> http://pico-systems.com/artwork.html for pictures of some of them.
> This is black Plexiglas. The top one is filled with orange crayon, and
> actually looks pretty nice up close.
>
> Jon