Normal Map Decals?

Airhendrix

Howdy all! I have seen (at least what I thought was) a way to use a polycard or decal material that would inherit the texture of any surface below it (or just be transparent) and apply a new normal without having to unwrap or spend the polys for vertex painting. I, however, am unable to do this correctly and figure that the UDK may not support this. Am I in the wrong? Is there a way to do this? I have attempted several things; decal materials with differing blend/lighting modes, polycards with odd blend/lighting modes, etc. Anywho, thank you guys for the input in advance, any help would be a godsend!

JamesWild

I don't think this is possible in a forward renderer without drawing a separate copy of the objects projected onto for every decal on the object; unlike Cryengine or another deferred renderer where the unlit colours and normal of the surface are stored and the lights are done after (hence deferred) in a forward renderer like Unreal all there is, is the final surface colour, multiplied against the lights. It's just not possible, sorry.

Airhendrix

Thank you for the reply! I had figured that may be the case, and hadn't delved into the rendering engine or technical side too far in teaching myself yet. Looks like I may be rebuilding in Cryengine!