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Re: gEDA-user: Thermals on Pads

On Sun, Jan 30, 2011 at 11:13:27PM -0500, rickman wrote:
> On 1/30/2011 4:47 PM, Martin Kupec wrote:
> > On Sun, Jan 30, 2011 at 04:37:17PM -0500, rickman wrote:
> >> What geometry problems do you have?  There are plenty of references in
> >> regard to thermals.  I don't recall seeing any other than bridges that
> >> span a uniform gap around the pad.  The only variation I can recall is
> >> the number and rotation angle of the pattern.   But most, if not all
> >> that I have seen use four bars either along the x and y axes or at 45
> >> degree angles.  I think there are even some built in commands for this
> >> in the RS-274X Gerber file spec.
> >>
> >> Or am I missing something?
> > We already do support bridges with rounded corners. And what we
> > do not support is anything suitable for TSOP package pads(long thin pads
> > near to each other).
> >
> > But the big problem with you current implementations is the size of the
> > bridges. The size is somewhat magicaly calculated from the size of pin
> > and from the size of clerance. But this is neighter working nor probably
> > right.
> >
> > With big clerance the shape becomes completly bogus(at least for the
> > rounded versions).
> That surprises me that the bridge width would be calculated rather than 
> specified.  What's the idea behind that?  Isn't it a simple matter to 
> let the designer pick the dimensions both for the width of the bridge 
> and the width of the clearance?

I would not argue against it.

So shall we change the code in a way, that older files gets current
calculation and newer ones has thermal specification in file?

This opens discussion how/what to specify.

	Martin Kupec

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