Texel Density and scale in UVS? workflow between blender and substance painter
Hello, I know a little about 3D but just recently I'm experimenting with painting my models in substance painter, that's when I first heard about the concept of texel density. Usually what I did was work on real scales in blender, for example if I made a robot that in my mind would measure approximately 3 meters, in blender I made everything at that scale, then when doing the uvs and assigning the texel density I only saw what it was the density that allowed me to have the largest size to take advantage of the 4k texture in the best way
But recently a friend gave me one of his models and I worked on it without thinking so much about the scale, when I realized the model of a character measured 100 meters, so when I did the uvs and assigned a texel density I realized that none of my presets fit in a 4k texture and that was the first time I realized that the scale of the objects (viewport) affects the scale of the uvs.
So my question is what would be the correct workflow to have the best texture quality? For example, the correct thing would be to assign a density of 20.48 and make the model smaller until all the uvs enter a 4k map?
i'm confused :/
Replies
yes, if you make the model smaller you'll be able to fit it on a smaller texture - not because it's smaller in the viewport, but because it's smaller in the world.
is it supposed to be 100m tall?
If the answer is no then you need to scale it down to the correct size - not just because of texel density but also because some processes are sensitive to scale (eg. some types of bake can use world units)
If you're not putting it in a game/diorama with a load of other assets just pack the UVs as tightly as you can (account for padding etc) into whatever texture size you feel like you need to make it look nice.
If the answer is yes there are more things to think about
Maybe the units setup between both your 3d apps is different (he works in cm you in m?). If you send assets back and forth, might be good to make some tests first, to ensure everything is in sync. But yeah, always good to work in actual dimensions.
"so when I did the uvs and assigned a texel density"
"i'm confused :/"
You're confused ... because there's no such thing as "doing UVs and assigning a texel density". This simply doesn't exist - or perhaps, you are being confused by a tool introducing the concept of "texel density "in its own way (for instance scaling UV islands in proportion to the scale of the model and in relation to a desired texture size). Wich is fine of course, and can be useful - but that's still not an inherent quality of UVs.
UVs are just XY coordinates ; and "texel density" is simply a relationship between a measurement in the game world and a number of pixels. For instance, deciding that one meter should ideally be covered by 100 pixels, or 256, or 512, or anything else.
That's all you need to know in order to decide the texture resolution of standalone asset like a big or a small robot really - and it can be easily figured out by using a test texture with squares of a known amount of pixels (to compare to other assets that have been authored earlier at the proper texture density for the project). But of course this is not a 100% strict rule, as your assets will also have a certain budget allocated to them that you can't go over.