although far from conclusive confirmnation of leo's thesis, i can say that i have never seen this issue and i have never used sorted (always been careful to check 'raster')

ds

_______________________________________________________________________
Integrated Controls, Inc.           Tel: 415-647-0480  EXT 107
2851 21st Street                    Fax: 415-647-3003
San Francisco, CA 94110             www.integratedcontrolsinc.com


Brad Velander wrote:
Good job Leo,
        I will have to  drag out a couple of designs and check their Gerber 
settings. Maybe play with them a little to see if I can cause the problem again 
and then eliminate it as well with your fix. Just to confirm absolutely that 
this is the solution to when I saw these issues as well.
        However I do know from my experience that tweaking pour outlines also 
fixes it, since all of the occasions where I saw it were along pour outlines.

Sincerely,
Brad Velander
Senior PCB Designer
Northern Airborne Technology
#14 - 1925 Kirschner Road,
Kelowna, BC, V1Y 4N7.
tel (250) 763-2329 ext. 225
fax (250) 762-3374



-----Original Message-----
From: Leo Potjewijd [mailto:[EMAIL PROTECTED]
Sent: Tuesday, September 27, 2005 5:51 AM
To: Protel EDA Discussion List
Subject: Re: [PEDA] arcs in Gerber go the wrong way


At 19-9-2005 14:31, Leo Potjewijd wrote:

On the PCB (P99SE) all my arcs look great, even on the print preview.
But in the Gerber files some, not all, are wrong: the start and end in the right places, but go the wrong way around. So a 90 degree turn ends up as a 270 degree turn with another center and shorts stuff......


And I am pleased to tell you all what the cause of this was. (drum roll, please ;)

In the 'Advanced' tab of the Gerber Setup screen (right-click on gerber outputs in CAM Manager) is a radio button 'Plotter Type'. As soon as this is set to 'Sorted (vector)' the trouble starts: random inversions of arcs and even deformation of texts.....

There must be an indicator to identify the arcs that go wrong from other elements, but that has not been found. Probably something like 'sweep angle divided by trace width, multiplied by the quotient of X and Y location relative to the nearest via, plus the clearance of the next two items in the PCB divided by the layer; when the third digit in the answer is even the arc is OK, otherwise the direction will change'. Or maybe just the electronic equivalent of flipping a coin, who is to tell.....

I set that radio button back to 'Unsorted (raster)' and the output was as I expected it to be the first time.


Leo Potjewijd
hardware designer
Integrated Engineering B.V.

[EMAIL PROTECTED]
+31 20 4620700




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