Fake roughness map

deohboeh

Is it possible to blur based on mask intensity in udk material editor? Since roughness does something similar I was wondering if it could be used to cheaply mimic pbr...

Quack!

Sure.

But blur what? Blur realtime reflection? Blur a cubemap? Widen a specular highlight?

A simple fake cubemap blur would be to use two cubemaps, one sharp and one blurred, and lerp between them with your 'roughness' mask. There is a whole lot more complicated stuff that can go on, but it is a very basic replacement.

Why not just use UE4?

BARDLER

Someone hacked it into UDK http://www.polycount.com/forum/showthread.php?t=124934

Like Quack said though, it would be a whole lot easier to just use UE4.

mAlkAv!An

Instead of using 2 environment maps you can simply sample one texture at different MIP levels, based on a roughness map.
If you don't like cubemaps look for equirectangular maps.

deohboeh

Thank you guys! I saw through all of the stuff. Its super helpful. I got UE4 and tested it out at first I was apprehensive because my computer is low spec. Then I placed all my assets inside. It works like a charm! I don't have to jiggle endless number of things for materials the reflections are amazing! And Dat Content Browser!

Also is it possible to go through mip levels on a realtime reflection of a render to texture cube?

Dexyn

I've looked all over for the Material Expression being used in the equirectangular maps that were posted above but to no avail. Specifically, I can't for the life of me find the Materials with the X and Y attached to them.

deohboeh

Do you mean tan(x,y)? Have you tried searching tan?

mAlkAv!An

These are custom nodes, 'acos' and 'atan2' is not available via the default nodes.

deohboeh

How do you create such a node?

mAlkAv!An

https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/ExpressionReference/Custom/index.html
Use the code from the screenshot, "return atan2(x,y);" and "return acos(x);"

deohboeh

Thanks! This is very helpful!