I've followed this guys tutorial filling up a jar with jellybeans... he used a cloth modifier to add dimension to the reflections of the jar glass (using the Octane Renderer). The problem was, the cloth modifier extruded the surface outward which made him have to create a smaller lower poly collision object version of his jar inside such that the jelly beans
wouldn't look weird smashing against the inner surface.
Then I saw a soft body tutorial I think from eyedesign
and I got an idea: I want to make a model with a transparent abdomen
and fill it with a few homunculi (with my face of course) bouncing around inside like the soft body eyedesign tutorial, BUT with the added "thickness" and better rendered glass of the jelly bean jars... my best idea is to duplicate the model, make it smaller, delete as many loops as reasonable, and bridge it closed for the little me's to bounce around in.
That might work for the abdomin alone (but probably not the short shorts). The problem is the same as for extrusions with bevels or rads on them. If you make the rads too big they start intersection themselves in the corners. For the cloth, as you start "extruding" inward the geomtry can intesect itself. On an opaque object you might not notice (although it might up the render time) but in a transparent object you may see the kinks, odd index of refraction artifacts and odd lighting issues with ploy's passing through each other (depending on your trani settings in the the ray section of the render settings.)
However if the shape is a smooth shallow curve like a womans hourglass (mine tends to form the opposite shape) that might have enough play so the inward facing polys are just "projected "smaller than the outer ones but don't actually intersect.
If you are animating the figure that may be a problem since the bending of shapes with bones tends to create poly intersections even on the best of days