Turn off cladding layer by setting to None

[gyger]

I think it would be very convenient to have the possibility to turn off the cladding layer. I understand that one can also just ignore it, so if this is the preferred option, please close the Feature Request.
Otherwise I would suggest the possibility to set cladding_layer to None to then not create one.

[Johny-Leo]

This can be easily achieved by deleting all elements (mostly polygons) in layer 1 and 2 (default boolean layers) of your final cell. For instance:

cell_top.remove_polygons(lambda pts, layer, datatype: layer==1 or layer==2);

This still may not give you flexibility to rename all layer numbers, but probably not a big deal.
The difficulty of directly "turning off" layer 1 and 2 is probably in the boolean operation of gdspy, which tends to keep the entities from different layers before the operation (if operation is on the same layer, the entities before operation do not show up in the operation result).