Using a tiling texture along with a normal map for a prop?

jordank95

HI there. Trying to figure out how to texture a large prop. I have a pretty large piece of furniture that I'm gonna need to use tiling textures on. But I also want to bake down the high to low poly so I can get some nice rounded edges as well as some other normal detail on the handles of the drawers. If I used one UV channel for the normal map, how would I apply the tiling textures to this? Just a little confused about this process and I can't seem to find a tutorial.

Thanks

PolyHertz

What program do you want the result displayed in?

jordank95

PolyHertz said:

What program do you want the result displayed in?

This for UE4

ZacD

How it specifically works depends on the engine. But tiling textures on top of other textures are often referred to as detail textures, detail normals, etc. 

Here's a guide on how to approach them with UE4
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/HowTo/DetailTexturing/
(The approach may change a bit with 4.19 material layering)

jordank95

ZacD said:

How it specifically works depends on the engine. But tiling textures on top of other textures are often referred to as detail textures, detail normals, etc. 

Here's a guide on how to approach them with UE4
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/HowTo/DetailTexturing/
(The approach may change a bit with 4.19 material layering)

Hmm, maybe my question wasn't clear or I'm not understanding correctly. I just have a bigger furniture wooden prop that I baked down some normal information from a high poly version just to get some nice rounded edges as well as some other small details on the handles. I want to use a 2k normal map on the mesh, but instead of using a regular 2k albedo map on the mesh, I need some more resolution. So I want to use a tiling wood texture. How can I set this up? Do I do this by using 2 UV channels? If so, how would UE4 use a lightmap on this asset? Is there such thing as 3 UV channels on an asset?

ZacD

How can I set this up? Do I do this by using 2 UV channels? 
Typically yes, you need to align the UVs with the wood grain. If you could try to create a UV channel that works for both the tiling and the baked normal map, but depending on the asset, that can get really tricky. And UVs don't take up much memory, you're better off using an extra UV channel than wasting texture resolution on a less efficient layout. 

If so, how would UE4 use a lightmap on this asset? Is there such thing as 3 UV channels on an asset?
Yes, you can use 3 UV channels, you'll have to tell UE4 not to override the UV channel on the static mesh import settings. Using the static mesh editor, you can have UE4 generate it's on lightmap UV based off one of the channels you imported. Or you can create the lightmap yourself and just import it. You'll have to tell the static mesh editor what channel to use for the lightmap. 

poopipe

Be aware that normal maps are affected by tangents stored in the uv channels - ue4 only knows about tangents in the first channel.


To get around it. . 
You can generate them for other channels in a shader (probably not cheap) 
Or
You can ensure that you don't rotate/flip/non-uniform scale the uvs in uv2 compared to uv1

jordank95

ZacD said:

How can I set this up? Do I do this by using 2 UV channels? 
Typically yes, you need to align the UVs with the wood grain. If you could try to create a UV channel that works for both the tiling and the baked normal map, but depending on the asset, that can get really tricky. And UVs don't take up much memory, you're better off using an extra UV channel than wasting texture resolution on a less efficient layout

Thanks for replying. Still a little confused. Why would the second UV channel need to line up with the wood grain? Ultimately I’d just UV my asset to the tiling texture and rotate all the shells so the grain is going the correct way. And scale up the UVs in maya and move them around outside the 0-1 space until I’m happy. 

Is there a better way to do this?

ZacD

Nope, that's a fine approach.