as far as I know, clipping planes are always “true”, infinite planes. This limits the possibilities (such as clipping away a corner of a model or a piece of pie.
It would be cool if there could be the option of limiting the clipping to the part of the half-space which can actually be projected on the clipping plane Rhino object (which has physical extents).
Alternatively, a clipping object (such as a box) could be used to achieve a similar or even more powerful effect - subtracting temporarily parts of the model.
You know you can have more than one clipping plane in a view, don’t you? Some experimentation will show you how they can be used together and whether you can get what you want.
I used to have an experimental feature in Rhino WIP for Raytraced where one could designate an object as clipping volume. Currently disabled though, but I hope to return to it soon.
