Re: gEDA-user: pcb layer groups

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Thu, Jan 05, 2006 at 11:50:52AM -0500, DJ Delorie wrote:
> 
> > It's slow even without it.
> 
> I checked out your board.  You have 24 overlapping polygons forming a
> single contiguous ground plane, and your "thermals" all mostly at odd
> (i.e. not 45 or 90) angles.  Try using a single polygon for the ground
> plane, and for SMD thermals try using short traces parallel to the

No. This makes small garbage triangles in the end which will have to be
replaced by breaking the polygon anyway.

I did exacly what you say for my first board and then cursed I have to
break the polygon and remake it again from small pieces.

> axes (0/90/180/270 degrees) coming out of the center of the pad's
> edges.  I tried just replacing your polygons with a single one and it

Why? I remember attending computer graphics lecture and remember that
time complexity of drawing of line is the same for line with 45 deg
angle as for any other angle.

> was a bit faster, but not nearly as fast as thindraw.
> 
> Hmmm... I wonder if we could add a "this poly is a rectangle" flag
> (internally) and speed this up a bit?  I suspect the big time use is
> in the masked layer copy, though.  To do clearances, we first create a
> mask, draw all the clearances to the mask, then use that mask to draw
> the polygons.  This appears to be an inherently slow operation.  Yet
> another case where "hide polygons" would be a useful option.
> 
> You should try using thindraw for boards like this, too.  It's a LOT
> faster, and you'd notice that you have two sets of thermals that
> aren't on pads.

When you turn on thindraw it starts drawing garbage - pieces of filled
polygons all around. At least in the times I used to try to use it. Now
I never try even turning it on.

CL<