Keep size ratio of objects when UVing

[Anonymous]

Dear All,
I wish to lay out the UVs of one of my characters. It is built up of LOADS of objects so I can't do this one by one.
Please be advised that seams are not an issue as I plan to texture it in MARI using 3d paint. I tried auto mapping, but when I use it on multiple objects, it scales all objects one by one so it fits perfectly in the UV space. The thing is, if I command a move (button right above unfold), it sets all my UVs to fit in the space, but it gives equal space to each of my objects. So a tiny nail gets as much space as a wall.

I wish to know if there is a tool that keeps the size ratio of my objects when mapping multiple objects. I tried UV auto ratio but it does not work with maya 2015.
Does either this version or Maya 2016 have something to keep the ratio?
Thanks in advance.

[Anonymous · Accepted solution]

'Layout' , in the Polygons menu of the UV editor. And set the settings as follow...

1 layout tab:

-check "single or multiple objects"(non-overlapping)
-Prescale: world

2. Layout Settings
- Shell Layout: Into Region (most of the time, project and 3Dpainting software/workflow dependent, could we say)
- Scale mode: Uniform (obviously! 🙂 )
- Shell Stacking: bounding box
- Rotate: 90° for architectural generally, otherwise set as per your own preference, this won't affect the relative ratios.
- Shell spacing: depends, base upon your intended texture size, and personal preferences regarding padding.

But since you are using Mari, you might also want to use UDIM uvs, and eductate yourself about that if you are not familiar with the subject yet. For characters, it's quite common nowadays, especially for Mari texture artists.

hope this helps! 🙂

[Anonymous]

Thanks for the reply, I definitely check that out.
I have not heard of UDIM yet but this character goes to a game engine, i do not know if one can use it that way 😕

[Anonymous]

one more thing. I have my character without anything done for uvs.
I do the auto mapping THEN do what you said, or...?

[J450NP13]

Create a shader and use this as the texture to get your uv's scaled correcdtly.

[Anonymous]

What you said, worked fine, thanks 😄
Now the textures painted in MARI are not that ugly pixellated. The ratio is decent now.
I do not think however that one patch would be enough to paint uvs even for games 😕 When I close on in the textures they still seem pixellated 😞 do you have experience in this? Is one patch usually enough - for games?

[Anonymous]

Glad I could help.
>>>"I do not think however that one patch would be enough to paint uvs even for games"
Depends on your texture budget/size, and... yeah, in rather recent games (less than 3 years old, so that's all relative, lol), two tendencies prevails:

- overal similar texel ratios for most uv shells, like what you wanted to achieve here (so, good! 😉 ) with the exception of the head (for characters), which can be scaled up so as to get more uv space, deliberately.
- or using multiple UV _SETs_ (hint: check that in maya helps) per character asset. Generally one for most of the body, arms+legs and occasionally weapon(s), and a second one dedicated to the head, hair and eyes.

But before delving into multiple uv set, If I would suggest that you get familiar with NON-auto UV unwrapping. Start by watching these two videos:

Steven Roselle's UV Editing Overview: https://www.youtube.com/watch?v=1ZJx3xr0xOM

and this one two: UV mapping made easy, by James Taylor.

Auto Unwrap is used to create basic, non-final UVs, so EVEN when you intend to 3D paint your textures it shouldn't be the final state of your UVs. Auto unwrap will most of the time get you a bit too many uv Island/shells... and since you have padding between uv shell you're potentially wasting texture space... not to mention diverse issues when viewing your character from a distance, depending on how your texture mipmaps handle these padding pixels.

Conversely, too few uv shells (and seams), and you will _also_ most certainly "waste" texture space (and get stretching).

Proper UV unwrapping is an art in compromise 😉

[Anonymous]

You know you business, m8 😄 Sorry to hold you up, but I have one more question about this multiple uv sets stuff, and about game dev.
So I look it up in Maya and found UV sets in the UV texture editor. There I can Make as much sets as I wish, of course for the cost of multiple mats per object in my mage engine. how does the game engine interpret this? I mean, for example lightmapping in UE, a lightmap uses only the 0 to 1 space. Anything I have outside is marked red and ultimately did not work (I tried using multiple patches and it works if I have exported my stuff with multiple materials attached to it, one per patch). Now do UV sets work similarly, or some other way? I have a cyborg or whatever character with no facial expression, plan to put it in an FPS game so the arms need to be detailed the most. I create 2 sets(from uv editor/uv sets), one for the arms/fingers, one for everything other, apply 2 materials before exporting the fbx and I'm done? in UE4, for example, I can chose which set I want to be the light map. Then I have to create yet another set with everything on it so UE can bake in the lights to all objects?

[Anonymous]

ah, I am sadly not familiar enough with UE4, though I believe that it handles multiple UV sets per asset, through the use of additional coordinate nodes, and actually calling them "index", maybe, instead of "set(s". Googling "multiple uv set unreal 4" should get you the answer, that or just asking on one of the Unreal community forums. 🙂