add fill areas (thermal zones)

[cooked]

see following links for considerations on PCB temparture and design

• https://www.mclpcb.com/blog/pcb-temperature/

[cooked]

possibly we could run copper zones all over the place since the (relative) permeability of the copper, air/freespace and FR-4 is the same (and = 1)

• https://www.engineeringtoolbox.com/permeability-d_1923.html)
• https://www.nde-ed.org/Physics/Materials/Physical_Chemical/Permeability.xhtml
• https://www.edaboard.com/threads/what-is-the-relative-permeability-for-fr4-material.221796/

there's still the trade off between how much copper goes into coils and how much goes into creating paths/copper areas to keep the PCB cool (likely the exit point for the eat is at the outer edge where the copper can go in contact with metal casing of the motor)

[cooked]

thermals are now done on all layers

z = pcbnew.ZONE(self.board)
ls = pcbnew.LSET()
for l in self.layset:
    ls.addLayer(l)
z.SetLayerSet(ls)

[cooked]

implemented, see do_thermal()... it only generates annular copper pours and does some stitching, but no advanced cooling features like testing with inner layer thermal "wires" or "fingers"