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Re: gEDA-user: pcb crooked traces



Rather than picking an arbitrary grid I have found a happy mix of most of the small pitch metric parts (0.65 mm pitch MSOP, SSOP, TSSOP) and a 0.1625 mm grid. I typically use 6/6 space/trace design rules which most houses work with ok which is the same as my grid (give or take the metric/inch difference). The traces are on a two grid unit pitch and when I go diagonal, I just offset the corners on adjacent traces to get a good approximation to the space 7.5 mil. I don't have to worry with an automatic tool to pack traces which I think makes rip-up and rerouting easier.

When I have other pitch parts, I just route out from the part and the second vertex will be on the grid. BTW, the tool I use can route so that the traces are always on right angles or 45 angle. Does PCB do that? Then you don't get odd angle traces.

Rick


At 10:29 AM 10/7/2010, you wrote:
>> I cannot get rid of the jagged diagonal lines on my design. There's lots of them. The picture shows a couple of examples. I've tried different grid sizes, line widths, but nothing fixes the problem. Redrawing them in order to eliminate any sections does not help. On PCB, it shows at some zoom levels but not others. It is in the gerbers as well and it is in the photo-mode picture I attached.


Another thought,  When I am laying out mixed pitch mm vs mil parts, I
often leave the grid at a comfortable 10 or 25 mil setting. Turn on
snaps to pins and pads. Then I largly ignore the grid.  What I am
saying here is that I Use the grid as a guideline.

So to accomplish this I draw from the off grid pin out to the pcb and
let the 45degree tail end on the grid.  then off to the rest of the
layout, on grid.

When that tail is not quite correct, while drawing I use the u key to
undo the 45 degree tail,  this leaves the off grid stub that i can
continue drawing from.

Having a small grid usuially allows me to make a messier layout.


If these things don't help then we have a bug.....

Steve


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