Hi Colin,

> He's using Rhino, so I think that you might need to create a
> closed curve for it to work correctly in Rhino?

Yeah probably - Rhino isn't able to do booleans mixing solids and curves directly like MoI. So using Rhino you would probably make those closed, extrude them with "both sides", and then use boolean difference using the extrusions as cutters.

Rhino does have a separate "WireCut" command that will cut a solid by a curve (the curve can be open), but it seems to only work using a single curve cutter at one time, so you would need to repeat it 2 times to cut this object.

- Michael