Modeling and blending normals

KurtR

I think I understand this, but I somehow keep confusing myself when I am trying to work with it. I am used to doing just highpolys, then bake down. Now I want to try to make a space corridor thingy with Ndo and Substance. What I show in the image is a trim sheet and a wall map I have created. The idea is that these are normals. The wall in the viewport is actually the same wall, just with each sheet and I have it just as a color map just now to see the edges better. The trimsheet I use to create some beveled edges on the mesh, while the wall sheet is for the actual wall details. But here I got slightly confused. Do I use a second UV channel, and if so how do I blend these then in UE4? Any other links, tips or help on the subject is much appreciated. It's mostly the approach to creating nice rounded edges from one sheet, and details from another, then putting it together in UE4 that confuses me slightly.

musashidan

In Max you can visualise it better by applying the normal map to display in high quality. Add a second uvw mapping modifier set to box and a different uv channel and have this as your tiling material. The first channel and unwrap mod being your trim detail sheet.

Also, this approach requires more geo for your low-poly, in that it becomes more of a mid-poly. You need to add extra support loops to control the shading.

If you want to see the entire process in detail from Max to UE4 I would recommend this:

https://gumroad.com/l/tutorial/80lvl

KurtR

@musashidan Thanks for response. Appreciated. I have barley looked at that approach, but I didn't particularly like it at first glance. But I should probably look better into it then. I was contemplating just doing the trimsheet from Ndo first, then adding it in with my lowpoly in SP and then adding normal details in there, but maybe this actually is a better approach. The way I was thinking about it seemed so cumbersome.

KurtR

Oh, and I don't bother to much about the normals in max. I have TS tools set up and Expresso exporter, so my UE4 scene is always open and I can update both geo and texture in a second and see it in UE4 directly.

KurtR

@musashidan Could I bother you with another question. How common is this technique from the Gumroad link in the game modeling pipeline contra doing straight out HP to LP modeling/bakes and do you have some other general input on the topic?

Obscura

Hi. You could use a second uv channel, yes, but Unreal doesn't generate tangents for it by default, so the material setup isn't really straight forward. There are 2 nodes that you will need to use. "derive tangent base" to make tangents for the second channel, and "blend angle corrected normals" to blend the 2 normals. Its a common approach these days in hard surface environment creation by the way. You save a lot of texture memory.

KurtR

Thanks @Obscura . Appreciated.  Ill dig into this. I am looking at the suggested gumroad by musashidan now as well, and it seems to actually answer some of my questions as well. I think my mindset was a bit off, and I need to adjust how I think about this.

poopipe

Obscura said:
 "blend angle corrected normals" to blend the 2 normals. 

Bugger it,   I've been doing that bit manually 

This is a fun technique and a really good way to handle massive objects that need fine detail on their surfaces.