On Sun, Sep 12, 2010 at 03:40:24PM -0400, DJ Delorie wrote: > > > > With flex cable, "top" and "bottom" aren't limited to one layer each. > > > > Aren't they? > > No. Different areas of the cable may have extra layers or pcbs > attached, changing the number of layers in that area. So one drawing > layer might be "top" on the left side of the cable, but "inner" on the > right side. >
Should we support this? What problems will we encounter if we allow layers to have arbitrary geometries? It looks to me that our "top/inner/bottom" distinctions will then only appear (a) in footprint mode and (b) when importing footprints. In all other cases, we simply have a layer stack. > > What use case is there for layers that map to multiple physical layers? > > Single solder mask for both sides. Keep-outs. copper heatsinks. > stripline. > All of these make sense for individual components, not for entire layers. > > > Why one? Why not save it? We already save rats to file. What about > > > layers that don't correspond to a physical layer? > > > > > > > Why have a different number than one? I could not think of a good reason > > for this. > > autorouter might use it to store information. DRC might. I don't > know what future uses, it just seems that "one" is a special case. > Why not just have a "save me" flag, and let each layer decide if it > needs to be saved or not? > > Paste buffers (cut-n-paste, not solder paste) might need multiple > temporary layers. > What are we talking about? I meant one layer-stack per board. Adding multiple virtual layers for whatever you can think of, is fine. > > > keepouts are just another layer. Let DRC worry about what to do with > > > it. > > > > Ah, but what happens when you want a keepout on all layers? On one layer? > > For only HV lines? For footprints but not traces? All these have been > > mentioned on the list, and don't work well with "keepouts are just another > > layer". > > I meant, if you have a keepout layer, it's just another layer. I > didn't mean to imply that there weren't other ways to specify > keepouts. > Fair enough. Andrew _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user