Orcad: carbon pad

If your switch pad is moderately complicated, create the pad outlines in a 2D drawing program like AutoCad or the drawing package that comes with layout. You can import the the graphics into Layout via a DXF import. You need to look at the maxdxf.ini file in the Layout installation directory for instructions for layer names. When you import the DXF into a Layout footprint, you will have obstacles. Edit the obstacles to place them on the proper layer, give them the proper obstacle type, and attach it to a pin. You will have a beautiful footprint which will draw oohs and aahs.

Not convinced this will work as the final pad has to be able to be described by the Gerber command set. Just tweak the pad until it is right in orcad.

That's just a question of the right conversion programs. Starting with something like DXF, you can have something like CorelDraw output HPGL (it'll convert all the fancy curves, fills, etc. into the simple "strokes" that HPGL supports), and from there something like GerbView can convert HPGL to Gerber. Most PCB packages can import Gerber.

Of course, many PCB packages can import DXF as well, although which commands they support is often limited. Pulsonix, for instance, doesn't support the DXF "SPLINE" command, so I use the approach described above.

You know the use of ALL CAPS on drawings/PCBs have been slowly dying ever since the point where Xeroxing drawings (one of the main reasons ALL CAPS were used historically) became uncommon? :-)

The way you label nets is similar to how the LabView guys like to do it...

---Joel

I am assuming that he is using Orcad Layout, but he didn't use an uppercase "L" when he used the word "layout".

Obstacles are drawn with lines, thus, they can be represented by Gerber commands. You need to compensate your DXF drawing for the line width used in the obstacle definition.

The technique I describe works quite well. In Orcad Layout, you can import a DXF file to create a PCB max file or a footprint library file. You can't use polylines, however. After you import the DXF file, you edit the footprint by tweaking the obstacles that were imported from the DXF file. The tweaking might be to change the obstacle type from free track to copper area and adjust the width. You add a small padstack for your pin so your pad doesn't protrude outside of your DXF defined area. You associate the obstacle with the pin so it will pass DRC.

The last four boards I have done all required using this technique. My BGA packages with a predefined fanout are done using a similar technique, however, I have a program that spits out an ASCII MIN file which is converted into a footprint. It's all the same concept.

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That sounds interesting.