Comment 19 for bug 1732720

>(jp-charras) wrote For a custom shaped pad, one cannot define a suitable shape for thermal shapes.
>Therefore only the designer can connect (by a track) this kind of pad to copper zones.
>(this is not specific to Kicad)

Actually, Diptrace manages this just fine, see attached screen shot.
I imported a Diptrace design, and found the custom pads did not connect the same.

If you want to avoid the code complexities of doing what Diptrace can already do, a possible workaround would be to allow the Anchor pad info that is already in the custom pad, to spawn the thermal.

The thermal resulting would be very slightly different from diptrace, but there would be 2 spokes on the right hand pad. Instead of the horiz thermal being pad-edge-centre, it is anchor-pad-centre.
That's likely tolerable for most all users.

eg consider this database
(pad 4 smd custom (at 0.54 -0.325 270) (size 0.255 0.255) (layers Top_-_Pwr F.Paste F.Mask)
  (net 1 5V_Common) (zone_connect 1) (thermal_width 0.2) (thermal_gap 0.2)

The size of 0.255 has XYD that can be used to create the thermals

This needs a new menu item of 'Thermal relief to anchor pad' added to the PAD options, and then some decision changes in the code to use thermal code, that already works in KiCad.

This appears to generate thermals fine
    (pad 4 smd rect (at 0 -0.82 270) (size 0.15 0.15) (layers Top_-_Pwr F.Paste F.Mask)
      (net 1 5V_Common) (zone_connect 1) (thermal_width 0.25) (thermal_gap 0.25))
ie a Pad smaller than the spokes is managed ok.