Re: gEDA-user: Vias with zero clearance in PCB?

[bumpelo@xxxxxxxxxxx]

 > Perfectly?  Or slightly larger?
Ok, 0.02 mil larger

> We need a way to edit the arc angles with the GUI.  PCB has no
> problems with non-quadrant arcs, you just can't create them with the
> mouse.

The reason is that non-quadrant arcs necessarily fall off of the grid - in principle you can't move your crosshair their. Now that we can snap to line/arc endpoints, this really isn't an issue, so we can consider a more advanced arc drawing tool.

PCB can also handle skewed arcs (unequal horizontal and vertical axis), but that isn't supported by the gerber standard, so I proved no way to draw them. Some of the very old libraries still do that though.

> What we really need is a flag for pins/vias that means "dont' clear".

Which would have to be on a per-layer basis too. Personally I think we should add an array of say 2 bit numbers for each layer to indicate what style of thermal should be used on that layer. We could offer 2 finger rotatations, solid fill, or no thermal that way.

It's probably time to do away with the PIP flags. They were made in order to save time by pre-computing whether there is a polygon piercing, but now that the data is all stored in r-trees (I better make sure that polygons are too), it's pretty cheap to re-compute this as each pin/via/pad is encountered.


> 
> I thought about a board-global "vias don't clear polys" flag but that
> messes up wave soldering, I'm not sure how useful it would be relative
> to pin/via-specific flags.

I think it would be nearly useless. Most boards these days have both power and ground planes, so the vias had better clear some polys.

h.