UV'ing low poly models
Hey there everyone, I got a question about UV'ing characters, specifically for low poly, but I guess it would apply to any model which needs to utilize a lot of mirroring etc.
So I made my first low poly character today, I would post the flats but they're on my other computer. I went to unwrap it, with the intention of using a 256 or 128 map, and planned to do the common unwrap you see where the face is mirrored and has a dead straight line down the centre. But I couldn't for the life of me get it unwrapped well that way. I ended up just doing a seam down the back of the head + pelt kinda unwrap.
Does anyone know of any tuts or tips on how to unwrap this way, It looks a lot easier than it it!
I have more trouble unwrapping a 400 tri model making decent use of UV space than I do with a 4000 tri character!
Thanks
So I made my first low poly character today, I would post the flats but they're on my other computer. I went to unwrap it, with the intention of using a 256 or 128 map, and planned to do the common unwrap you see where the face is mirrored and has a dead straight line down the centre. But I couldn't for the life of me get it unwrapped well that way. I ended up just doing a seam down the back of the head + pelt kinda unwrap.
Does anyone know of any tuts or tips on how to unwrap this way, It looks a lot easier than it it!
I have more trouble unwrapping a 400 tri model making decent use of UV space than I do with a 4000 tri character!
Thanks
Replies
if you have a seam, maybe you have some mipmapping artifacts there. if you set your viewport prefs to unfilitered things shold be alright. but this is just a guess...
I guess I'm asking more about how to unwrap, like should I use pelt map for the head if I'm mirroring it?
My guess was that you unwrap the head, delete half of it and then mirror it so the UV's are on top of each other, but while this does produce perfectly overlapping UVs, the pelt map doesn't really work out so great, like I don't have that perfectly straight edge along my symmetry line. Should I use a different mapping projection?
Thanks
When I do it I delete half the model do the UVs for that half, then mirror it. I doubt you would automatically get straight line with any tools you have to manually push them that way.
that's the trick I was missing then, relaxing only part of the shell.
Thanks for the script too, how does it work? (havnt got access to Max on this comp).
and why have to mirror uvs once you delete half the geo you can jsut mirror the geo and the uvs will be stacked for you as both peices use the same uvs. Way easier imo.
It works like this:
Just make sure one half looks good (relax some parts, tweak some by hand and rectify some edges so you don't get distorted pixels later) and once done simply select that half using face selection and simply mirror it to the other side.
Another tool in TexTools (added in 3.1) is a snap to pixels button which will snap your selection (edge, verts or faces) in the UVunwrap editor to pixel boundaries. Its used like this:
The button for this is located on the Selection Transform Bar that pops up if you open the UVunwrap editor from the TexTools Toolbar. This tool is useful for very low texture work where snapping to pixel size really matters.
Also I would suggest working in a square UV size and once done with your 2:1 half just use the UVW xForm to extend it or simply use the recently added UV canvas tool in TexTools 3.2
Which just uses the xForm UVW modifier but does the math for you so you don't need to dig with reversed axis, 0-1 ranges and alike things.
When you mirror the geometry, if you've unwrapped the UVs already then the duplicated geometry will already have the same UVs. They will be right on top of the originals though so unless you have Mayas shade UVs on then you won't see it.
So the UVs are now 'mirrored' because you'll be painting the exact same thing on both UV shells but because one is overlapping and flipped, it'll appear as the mirrored image on your geometry.
It's difficult to explain but basically just unwrap the geometry in question (usually you'll get cleaner UVs if you unwrap before deleting half the mesh).
Delete half the mesh, and mirror it, then weld along the seam, done.
If you want to check it's properly UVd, click one of the verts on the UV shell (don't drag select otherwise you'll select the one underneath too) then ctrl-click - to UV shell, and move it a bit and you'll see you have an exact same shell underneath. Obviously undo after though so they stay perfectly aligned.
Why do you want to use W since there is only U & V ?
Little known fact - the UV baker bakes to the 0-1 space, to whatever is highest (most W). So if you've got overlapping, you can avoid the weird rendering issues by increasing the W amount on one of the mirrors.
This is also handy if you're overlapping UVs, like say you have a small bit that you want to have sitting in a black spot underneath some floating geo - just take your tiny piece and increase the W and you'll get a clean render.
You can avoid bake problems if you move the overlapped UVs to -1 on W. Same as moving them on U or V.
Except W can be messy... it's generally hidden unless you purposefully look for it (bad for team work), doesn't get preserved on export to other apps, and high W values can prevent selecting and/or welding UVs. Better to move on U or V.