Unreal 4 Car Paint Shader

curzed

I'm coming from lots of Unity experience but relatively no shader experience especially with these networks or nodes.

Jumping into Unreal 4 and the basic PBL setup (Diffuse, Roughness, Metallic) what can I do to try and push more realism? Also this may be a good opportunity for other people to learn as well?

I know there are quite a few parameters like adding fresnel or noise, I'm looking for something similar to the VRay Car Paint Setup. Any info or help to get me going or any specific nodes to use (all i have are constants) would be great






Examples

Jacky

Get a Lerp node(hold L and click on the canvas) and a Fresnel. Plug Fresnel into alpha of the Lerp and two of your colors into A and B and plug Lerp to Diffuse, then tweak fresnel values until you get the looks you want.

Shift`

I threw something quickly together, use the exponentIn to control the amount of Edge Bias.

ZacD

The important thing about car shaders is making it look like the material has 2 layers, it has really sharp reflections and then blurred "sparkly" reflections. I'm not sure there's an easy way to do that with UE4s materials.

haiddasalami

Take a look at Forza's material talk at GDC for a bit more advanced look at car paint shaders. Theres some code there if I remember correctly from attending the talk. Was a good talk about their material system.

Jacky

Yeah, thats about it. You can also use fresnel to get different roughness/metallic values at different angles. You may want to use a noisy normal map and use its red and green channels for roughness to achiever that kind of sparkly reflections.

almighty_gir

question:

why would you add fresnel like that? it's already incorporated into the brdf.

/anty/

Normally you need to have two layers. Base and clearcoat layer. Haven't tried yet but I guess will work. At leas I had it like that in UDK)
Base layer needs to be with roughness aground 0.5, might have metallic input ( 0.5)
Second "Top" layer needs to be the same as previous shader but with really low roughness and probably higher level of reflecivity ( 0.8- 1.0).
Blend both layers linearly ( you can try to multiply lerp mask on fresnel)
In theory this will recreate physical existence of car paint.
As well you may try to ad some SSS to coating layer ( seen some samples for Arnold render, they used SSS with really low value on car paint, not sure that it will work, but worth to try))

BARDLER

almighty_gir wrote: »

question:

why would you add fresnel like that? it's already incorporated into the brdf.

To fake the effect of two tone car paint.

almighty_gir

this is why i don't make cars

curzed

Awesome! Okay so I went ahead and added the fresnel and it already looks much better. I will try next adding normal map red and green channels as well as research Forza's GDC talk though I'm not much of a coder, it will still be useful.

curzed

Added normal map red and green channels for subtle noise, having issues with getting it show up more though. Its a 4096 texture with no mipmapping, what else can be done?

curzed

/anty/ wrote: »

Normally you need to have two layers. Base and clearcoat layer. Haven't tried yet but I guess will work. At leas I had it like that in UDK)
Base layer needs to be with roughness aground 0.5, might have metallic input ( 0.5)
Second "Top" layer needs to be the same as previous shader but with really low roughness and probably higher level of reflecivity ( 0.8- 1.0).
Blend both layers linearly ( you can try to multiply lerp mask on fresnel)
In theory this will recreate physical existence of car paint.
As well you may try to ad some SSS to coating layer ( seen some samples for Arnold render, they used SSS with really low value on car paint, not sure that it will work, but worth to try))

I will try this next thanks! How do I get two layers going?

Jacky

Use the Fresnel calculation for roughness as well. Then plug that Add of the normal noise to A and a constant of 0 for the B. You may want to consider multiplying(or Lerping 2 roughness values by using it as a mask again) that noise with a higher value if you want to increase its effect, btw.

Also, i don't think UE4's SSS is suitable for coating or car paint.

kalmax

hello wanted to know how to create this material in udk 3

kalmax

hello wanted to know how to create this material in udk 3