Hi DesertRaven, in MoI you can generate a solid pushed out from a curve by using the Extrude command.

You can also draw curves directly on surfaces if you have "Object Snap" enabled.

So that combination should let you do generally similar operations - the main difference is that MoI does not automatically embed curves that you draw on a surface to divide it, because sometimes you may want to use them for other things like as a path for a rail sweep or a different kind of surface operation like doing a revolve, etc... , MoI has a lot of different methods for surface creation and not just one single method like SketchUp and so that makes for a somewhat different workflow in MoI.

Please see this previous discussion thread for a video showing how to do some similar types of operations in MoI:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2215.1

- Michael