Hi Lordfox, some more information on this FAQ answer here:
http://moi3d.com/FAQ#Q:_Why_does_show_points_work_for_some_objects_but_not_others.3F

Basically when you have objects where surfaces are joined at "trim edges" MoI does not allow you to turn on those surface control points because it is very easy then to pull the surfaces apart and make a gap between what is supposed to be a joined edge.

Like Burr says above if you use Edit > Separate on your object to break it into individual surfaces then you'll be able to turn on control points for those surfaces.


re: some solids are fine,

- if a solid is made up only of "untrimmed" surfaces then that's a special case where you can turn on control points for the solid - that will be the case for a simple box for example. But when you have things made up of trimmed surfaces it's a different kind of situation.


It's not a big focus for MoI in general to do control point manipulation of surface point cages, usually you should be creating surfaces from curves rather than by trying to squish surface points around.

- Michael