Inverted Collision?

[Demorian]

Hello,
I have a problem that I'm not quite sure there's any way of achieving in Newton without coding it 'manually', I posted this in the Ogre forums as I'm using MogreNewt 2.0 and Mogre, but this is a more generalised question so I'm coming here for help instead. The problem is that I've created a tube mesh, and I would like to have the behaviour set so that when objects on the inside collide with the walls of the tube they roll around in it, it seems all collision shapes I set to it only work when something hits the outside of the shape, nothing for the inside, even after inverting the normals of the shape.

So my question is: How can I invert the shape to get the desired behaviour?

A more detailed description of what I'm trying to achieve and what has been tried exists at:
http://www.ogre3d.org/addonforums/viewtopic.php?f=8&t=10085&sid=e4cd554fc1d8a3755c441ffc0b650473&p=58708#p58708

Thanks for your time, Demorian.

[JernejL]

if you use a trimerh, you just set the face orientation to point inwards.

[agi_shi]

Inverting the normals doesn't matter. You need to invert the vertex winding, so if it's clock-wise, it needs to become counter-clock-wise.