Hi Mike - re: 3D shear - I should be able to make a Shear command that will handle doing a shear on a 3D object like that, but it should be a quite unusual circumstance to get an already sheared 3D shape like you show there that needs correction to be straight.

When there is a shear command, it's much more likely something that you would use to introduce shear to an existing straight shape rather than correct a sheared solid. You kind of have to put some effort into making a sheared solid in the first place.

Really to correct a sheared solid like you show there, I'd recommend duplicating the base curves at the bottom (and any other key locations) using copy and paste, and then construct a new solid using extrude/revolve/etc making a straight shape.

- Michael