How to Polygon fill with isolate 0?

Question

Hi There,

I'm trying to develop a ULP that detects the outline of the traces on a layer and converts them into gcode.
I know this has been done before, but I'm trying to understand how it works.

Anyway, what I've found is doing a ground plane fill usually ends up making a polygon that has a contour with the information that I want.

What i've tried is the following: (typing in the commands manually)

polygon _TEST_ 0.0001 (0 0) (0 400) (1000 400) (1000 0) (0 0)

ratsnest

This fills the empty space around the traces with a ground plane. But the ground plane is too far from the edge of my traces.
ideally, I would have the polygon go right up to the edge of my traces.

so I tried this:

change isolate 0.0001

polygon _TEST_ 0.0001 (0 0) (0 400) (1000 400) (1000 0) (0 0)

ratsnest

But I got the same result as the first commands.

I've also tried using 0 as the isolate value. But it always seems to keep it's distance and never approaches the traces closer than 0.4mm ish?

What have I done wrong?

Thanks

Josh

Former Member · Accepted Answer

After further searching, I've found what I'm looking for

Because I want the outline of the traces, it turns out there is a special polygon name to use that means DRC rules are ignored.

The relevant details are here:

http://web.mit.edu/xavid/arch/i386_rhel4/help/124.htm

Importantly:
change rank 6

and use polygon name _OUTLINES_

so the following works:

change rank 6

change isolate 0.0001

polygon _OUTLINES_ 0.0001 (0 0) (0 400) (1000 400) (1000 0) (0 0)

ratsnest

autodeskguest · Answer

Joshua Green schrieb:

I've also tried using 0 as the isolate value. But it always seems to
keep it's distance and never approaches the traces closer than 0.4mm
ish?

There also are minimum distances set up in the net classes and the

general design rules (DRC).

The largest of all applies.

Tilmann