Texel Density / Uvs / Quixel / UE4 / (Need Help)

MannyG

Hi,

I'm working on these panels/walls for UE4.

I did 2 sizes for modular pieces (panels/walls, ceiling, ground) 300x300 / 600x600 in Centimeters Units.

For all the panels/walls, I have 3 Sub/material iDs :
ID1 : Panels/Walls 
ID2: Frame windows  
ID3 :Glass ( Frosted glass )

I unfold each panels/walls (300x300/600x600) like that, you can see on the pictures. I need to stick my UVs to the border of the Uv space to avoid seems between each panels. UVs from ID2 are overlapping on ID1. I think its not important, because I have 3 Materials with UE4. But I can't use Quixel for texturing, I didnt find how to use Multi/Sub material from 3DS Max.

Then, I have not the same texel density between 300x300 and 600x600.  When I tried to get same texel density, Uvs islands became big or little.

I don't really understand how I can have the same texel density with my 300x300 and 600x600 panels/walls, and stick my UVs island to the border. I think it's impossible. 

Maybe, I should use 1k texture for the 300x300 panels, and 2k texture for the 600x600 panels.

Under UE4, I did a little test with tiling texture and 2 materials. 

For the 300x300, I used a TexCoord and 4 for the tiling. For 600x600 : 8 UV tiling.


My questions :
What is the right way to have the same texel density between panels/walls?
I need to use same texture and play with the UV tiling?
Need to use a 1k texture for 300x and 2k texture for the 600x? 

I would to know how I could use Multi/Sub Object Material with Quixel.


Texel density for 600x600 and 300x300, UVs overlapping



It's just a test to check seems. Dont want this tiles


TY

Obscura

Inside Unreal you could apply different tiling of 1,1 to the 300x300 one and tiling of 1,2 to the 300x600 one. Or, you could just scale the 600 one twice as tall on the uv map as the 300x300 one. Also, in the first UV channel they can go out from UV space 0-1 since you are using tiling textre. 

MannyG

Thanks Obscura, I checked your link for vertex normal, really interesting. 

Hope I will receive more help.

Obscura

There would be an another way, called tri-planar mapping. Its available in the Unreal engine material editor, and its a material function called "world aligned texture". But this would increase shader complexity so I'd rather recommend making good uvmap and let that do the job. What I would do to get consistent pixel density on modular buildings and stuff like that, is to just copy paste the same "uvw map modifier" so I can paste the same density on all of them easily. You could have one with 300x300 plane mapping. So they will automatically touch the edges of UV area 0-1, and even when you paste this on the 300x600 one, it will have the pixel/uv ratio of the 300 one because you didnt change the size of the mapping plane. An another way, and if you don't mind loosing some of the modularity inside Unreal, is to assemble, or partially assemble your building inside the modeling package. This would provide several optimization approached though and you would still have the modularity inside Max. So then you could just attach and weld the wall pieces and apply box mapping or whatever so they wouldn't even have to be aligned to the edges of the UVmap.