Udk Lighting issue

SnakeDoctor · Oct 2010

Ok quick question. I have a modular piece where I have deleted some polygons in the back the player will never see. When I put a dominate directional light it of course shines right through the backface of the model causing lighting problems. One guy mentioned somthing about making the material 2 sided. How do you do that with UDK or what can I do to not get this error? Would it of been best to keep those polygons in the back?

Thanks for the help

Sean VanGorder · Oct 2010

I'm not sure if that's what the problem is, but to make a material two sided, just check the box in the material editor.

SnakeDoctor · Oct 2010

Ok thanks. It did solve the problem, but if anyone knows a better way please feel free to let me know. Still wondering is it takes less computer power to render more polygons or make a material 2 sided.

gamedev · Oct 2010

The 2 sided material is more expensive than 2 sided geo, 9/10 times.

Rurouni Strife · Oct 2010

In some of the UDK models I've opened or looked into in engine, they tend to duplicate the object and reverse the face normals. That way the object has no back face problems like you encountered. Sure you have extra polys, but unless you have a crazy scene Unreal typically can handle them.

Reverenddevil · Oct 2010

Ya, I would avoid the two sided material route unless you are not worried about performance and its purely for beauty static shots.

The other route would be to instance a mesh that can cover the back and use that so you don't take a hit on a new unique mesh

or you can just create a simple plane with a black texture on it place it and scale it to fit the deleted faces of your objects to keep the light from shining through.

Udk Lighting issue

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