Options panel tickboxes have no effect… wotmy missing?
Clippingplane refuses to make fills if the object isn’t a closed polysurface (or closed surface)
It should imo as Rhino is a surfacemodeller and we import and modify 3D data that has issues all the time, like STEP from Solidworks, that never come in as solids.
We also need the ability to have a clippinplane c-plane feature, where the only things we can snap to are the clipping edges.