Hi NightCabbage, sorry I was writing my post above while you posted your other one.

> I called it "thicken" because I couldn't think of another way to describe it :)

In MoI it is called "Shell", and it is available under Construct > Offset.

Check out some of the illustrations on it here:
http://moi3d.com/1.0/docs/moi_command_reference7.htm#shell

It's very worthwhile to spend a bit of time browsing the documentation - it has a lot of illustrations in it that show what kinds of commands are available:
http://moi3d.com/1.0/docs/moi_command_reference.htm


However, Shell will have some difficulty thickening pieces made up of more than one surface, if their edges do not meet at simple angles. So the example you have there where the top has an angled slice on it will not shell properly, but if you do it on a simple straight piece like this before cutting the angled part, it will work, like so:





Then cut the angled top off after it has already been thickened.


You can be better off doing more stuff with curve profiles when possible though, so for example if you want a thickened object it can be a better idea to thicken your initial curves first by using Offset on them (in v2 there is a new "cap ends" option for offset to produce a thickened outline curve very easily), and then extrude that and you will have a thickened result right from the first extrusion.

- Michael