Are these inverted UVs okay?

Thane-

Are these inverted UVs okay? Anything change if its for the unity engine? If not okay, is there a way to fix them? I tried flipping horizontal, then "mirroring" horizontally to get them back into place as someone suggested, but it didn't work, still inverted. The geometry was mirrored (symmetry modifier) in 3DS Max, but i attached the sides together to weld verts, then applied the Unwrap modifier.

Eric Chadwick

Did you test it yet? The sooner you get it into Unity the better. That's the best way to see if it's right or not.

Those UVs should be fine. As long as your shader is set to tile the texture, which most Unity shaders do anyway.

One thing I noticed with Unity, when exporting FBX files from 3ds Max 2015, my UVs and vertex colors would be messed up on import. I needed to add a Turn To Mesh modifier on top to solve this.

Thane-

Okay, i will try and test it with unity. Thanks for the export tip!

Are inverted UVs in the main UV area not a concern as well? I had a bunch of them, but flipped them, was that unnecessary?

Sorry, im really finding it hard to get my head around all these concepts that relate to each other like normals, tangets, bi-normals, bitangents, uvs, inverted uvs. Ugh.

Thane-

*sigh*

Does the corruption you get look something like this? I am using the unity Xnormal plugin and have tried without as well, also with 1 smoothing group and my custom ones. I've not tried all combinations yet but i still have many years of life left so there is time.

This is the really really good version among my results thus far.

Eric Chadwick

Yeah that looks like the same problem. IIRC this was introduced in a specific version of Max, and may have been subsequently fixed.

In my models the UVs are randomly rotated, per polygon. But if I add a Turn To Mesh modifier, that fixes it.



Inverted UVs are completely fine. You can in fact do anything you want to your UVs. There are just a few things to look out for:
1. If you're baking normal maps, split the UVs for every hard edge. (You're making me hard. Making sense of hard edges, uvs, normal maps and vertex counts)
2. If you are re-using UVs (overlapping, mirroring), and you are baking textures (normal maps, ambient occlusion, etc.), then before baking you should move all the overlaps out of the 0-1 UV space. (http://wiki.polycount.com/wiki/Texture_Baking#UV_Coordinates)
3. If you're using a single unique UV layout (not tiling your textures) then make sure to leave enough room between the UV shells, to avoid seams from texture filtering. (http://wiki.polycount.com/wiki/Edge_padding)
4. Avoid adding unnecessary UV seams/cuts, as this increases the in-game vertex count of your models. (http://wiki.polycount.com/wiki/Polygon_Count)


We put more stuff about UVs here
http://wiki.polycount.com/wiki/Texture_Coordinates

EarthQuake

The uvs look fine in the op's image, the normal map detail is all where it's supposed to be. The artifacts here might be due to bit depth issues and/or compression.

http://www.polycount.com/forum/showthread.php?t=148303

Thane-

Thanks to you both.

Do i need to bake the model in Xnormal with the "turn to mesh" modifier on a model too or does this apply to just the model imported to Unity?

Eric Chadwick

Nope.

See Why is exporting to xNormal so painful lots of tips

Thane-

Solved the problem by setting the "format" in the options for the texture to "truecolor".

Note to self: please try the basic settings first before taking to strange religious practices to try and solve the problem, thanks.