No collision detection with back faces in voxel game. HELP!

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Hello everyone!

I'm creating a voxel game in Unity (sth. like Minecraft), and i've got a serious problem: There's no collision with backfaces (back, left and bottom block faces do not have collision). I've already tried switching all normals to positive or replacing left face with right face - 1.I think that Unity or physics engine recalculates normals somewhere, what makes backfaces come back.

PLEASE! Help me, my project is stopped for this reason and i've no idea!

Answer 1

Answer by Bunny83 · Nov 09, 2012 at 10:22 PM

The vertex normals are just used for lighting calculations in the shader. The direction a triangle is facing is dertamined by it's winding order. In modelling applications this is often called "face normal".

If a face points in the wrong direction, just reverse the winding order of it's vertices by exchanging two of them. Something like that:

 0, 1, 2  --> 1, 0, 2

It doesn't matter which indices you exchange.

edit
Just in case you haven't seen it, there's a Unity Minecraft starter package

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Kiel369 · Nov 10, 2012 at 03:00 PM 0

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Thank a lot. I've combined these triangles with flipped indices, with a normal ones creating a double-sided polygons where needed and it works fine.

Loius · Nov 10, 2012 at 09:51 PM 1

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No collision detection with back faces in voxel game. HELP!

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