Re: gEDA-user: trace calculation

[sdb@xxxxxxxxxx (Stuart Brorson)]

> > is that it is enough to just miter the corners of a 90degree bend,
> > or (better) use two 45 degree bends to transition between a 90
> > degree bend for all but the very highest frequencies.
> 
> Would it be useful to add an optimization that puts rounded corners on
> 90s instead of miters?  We already have the 45/45 automiter in the
> connections menu; adding a quarter-round option might not be that
> difficult.  We could certainly do one small enough to fit within the
> DRC parameters (i.e. if trace/space are 10, a 20 mil radius curve is
> almost always OK).

Again, my understanding is that you only need to bevel the elbow of a
90 degree turn, or better use two 45 bends.   You don't need to create
a round or circular transition.  Here's an article about it:

http://www.ultracad.com/articles/90deg.pdf

I wish I had Howard Johnson's book here, but I don't.  It's packed
away somewhere.  However, I bet he has something illuminating to say
about this.

Of course, if you want to create a round or semi-circular bend, that's
fine.  But it doesn't really buy you much.

BTW:  There are a lot of good SI articles at the ultracad side here:

http://www.ultracad.com/article_outline.htm

Stuart