> A "Chop" command.
>
> I find myself doing a lot of chopping up of solids. Draw a line, extrude into a plane,
> boolean or trim a closed surface with it, etc etc...

This is partway built into trim already - you can currently trim a solid with a line for example.

But it won't leave behind the piece of the cutting plane, it will cut the solid only. However if your cut left a planar hole you can fill that in easily by selecting the object and doing Construct/Planar. So that should work now for some cases.

I do want to extend this to be able to leave the pieces of the extended trimming object around as an option, and also build in some solid / curve interaction into the booleans like you are asking for. Not sure when though, there are some other things that I've got to finish up first...

- Michael