@Tim Edwards when you get a chance, could you explain how magic handles multiple derivations of the same layer? For example nwell is defined 3 times and pwell twice in the sky130 tech file. nwell

layer nwell NWELL,WELLTXT,WELLPIN
 and-not PNPID
 labels NWELL
 labels WELLPIN port
 labels WELLTXT text
...
 layer nwell pfetarea
 and-not COREID
 grow 180
...
 layer nwell EDID
 and POLY
 and DIFF
 and PSDM
 grow 685
 or ldmos_nwell
 grow 420
 shrink 420

pwell

layer pwell TAP,DIFF
 and-not NWELL,nwelcheck
 grow 130
 or SUBTXT,SUBPIN
 grow 420
 shrink 420
 labels SUBPIN port
 labels SUBTXT text
...
 layer pwell EDID
 and POLY
 and DIFF
 and NSDM
 grow 660
 grow 420
 shrink 420

Magic will simply generate output as stated; it will generate output multiple times for the same layer name if that's what's in the

cifoutput

recipes. The main "gotcha" when generating a layer multiple times is that each section is independent, so issues like gaps between layers created in two different recipes can't be eliminated by a grow-shrink pair of operators. The better approach is to make all of those

templayer

recipes instead, then OR them together for the actual output layer, then do the grow-shrink operators.