Raycast from outside a model to delete all inside faces? I'm working on a Lego project where I build models out of Lego bricks in LDD and then import them into Blender via various hoops - inside Blender I then optimize them before loading them into Unity for a small game.

The problem is that Lego has so much geometry inside a big model, because it consists of many small bricks that all have studs and at least 6 sides. 

I'm thinking that there must be some kind of tool that can raycast all around outside the model and then delete/group/select all internal faces. Do any of you know of such a tool or where to find more information on this subject? Even just a more correct term would be helpful for my google ventures :)



Thank you! &lt;3
One trick I used in 3ds max once, was to bake a tiny AO map.  Auto uvif you can.  Or maybe can vertex color as well.  

But basically whatever faces were totally black, I then selected / deleted. Since we're then basically fully hidden from view.