If I want to keep a certain texel density but can't fit all the UV's in the 0-1 space what can I do?

JWDD

This might be a stupid question, but I have a fairly large object that I want to keep at 8 px/unit but there wouldn't be a way to fit that in the 0-1 space of a 2048 map, even if I change just one of the shells to that range it doesn't fit the 0-1 area. So do I split the UV's into two maps? Not too sure what my options are...

Edit: Image for clarification. (and yes I can see the n-gons, they will be fixed in triangulation.)

Noth

well you could scale them all down proportionally, or you can have that big on one it's one texture and use UDIMs. You could also x2 the resolution for that one item and 1/2 the size of the island I think?

https://help.thefoundry.co.uk/modo/902/content/help/pages/uving/udim_workflow.html

JWDD

Ah I see I'll have to research that UDIM pipeline. A bit of clarification though, that one large shell is just one that I have changed to the correct texel density, the rest have yet to be changed (you can see the mirrored UV shell that hasn't been changed yet in the 0-1 space.)

Also with the UDIM workflow does it effect the process of baking? I use Substance Painter, so would that recognise the multiple UV maps and bake it down properly? How would I got about importing all these separate textures into UE4 for the final render?

JWDD

Also I would like to ask, is this texel density correct? I am looking at this post for guidlines since  this will ultimatly be imported into UE4: https://www.epicgames.com/unrealtournament/forums/unreal-tournament-development/ut-development-art/ut-environment/1672-standardizing-texture-density?6715-Standardizing-Texture-Density=

In which TeriyakiStyle mentions "8 pixels per unreal unit (uu) is a good target for fidelity" and since 1uu = 1cm in Maya 8px/unit is a good target right?

radiancef0rge

udims are not supported in game pipelines, post a picture of what your mesh is. 

JWDD

Ah I see, the highlighted object is the UV's I'm talking about here.

radiancef0rge

this should be a tiling texture, with uvs that go outside the 0-1 space.
i recommend this tutorial here: http://leonano.com/portfolio/texeldensity/
and this post here: http://polycount.com/discussion/91105/infamous-2-and-festival-of-blood/p2

JWDD

Thanks radiance that's really helpful! I take it I wouldn't be able to bake down a high poly or unique maps with this workflow then?

radiancef0rge

you could make a highpoly trim sheet and bake that down, sometimes that's helpful if you'd rather not create bevels and greebly bits in your texturing application.

an example of a similar technique can be found here https://www.gdcvault.com/play/1022324/The-Ultimate-Trim-Texturing-Techniques, however this method can be pretty bad for texel density if used incorrectly.