Do UV Shell/Islands need to be straight for good results?

ApolloFury

Hi, sorry if this has been asked a billion times (or in the wrong place) since I do not know the specific terminology for this question but do UV islands need to be in the same direction as the object in the 3D space? For instance if you look at the 'shorts' (or pants) in the screenshot - in the UV viewport (left) they are angled so that they can be placed more efficiently (L shaped) but in the 3D viewport (right) the shorts are in the upright position as usual.

Is this technically wrong? I am going to 3D paint this in Substance painter after.

(Also tips on how to UV this better is much appreciated)
Thanks. 

musashidan

It's more of an issue with hard-surface unwraps. The reason is aliasing in the bake. On a hard edge baked to a normal map the aliasing is much more apparent, especially at lower mips/resolutions.

Stacking/overlapping islands is a vital part of the workflow if you want to unwrap/bake/texture as efficiently as possible. Any parts that won't be seen - front/back or left/right - at the same time can be stacked. Also, things like the sleeves and shoes and other parts that won't be noticed as much, as say the character's face, can be stacked. Stacking/mirrored UVs can be done either at the baking stage by offsetting islands, or after the bake you can simply mirror/clone meshes elements.

it's still always good practice to unwrap/pack as efficiently as possible to gain precious texel density/pixel resolution. A good unwrap/pack is often overlooked/rushed by beginning artists, which is foolish as it is a huge factor in final quality especially wit game assets.

The islands don't have to be facing the same direction(unless baking lighting or other directional effects) In older 2D texturing workflows it was important to arrange islands logically and facing the same direction for ease of texturing, but not so much in SP. There is a strange viewport bug in SP, though, that shows the seam on islands connected by a UV seam, but facing different directions. It will be fine in UE4/Unity/etc though. Here's an example of the bug:

islands facing same direction

islands facing different directions

UE4

ApolloFury

musashidan said:

It's more of an issue with hard-surface unwraps. The reason is aliasing in the bake. On a hard edge baked to a normal map the aliasing is much more apparent, especially at lower mips/resolutions.

Stacking/overlapping islands is a vital part of the workflow if you want to unwrap/bake/texture as efficiently as possible. Any parts that won't be seen - front/back or left/right - at the same time can be stacked. Also, things like the sleeves and shoes and other parts that won't be noticed as much, as say the character's face, can be stacked. Stacking/mirrored UVs can be done either at the baking stage by offsetting islands, or after the bake you can simply mirror/clone meshes elements.

it's still always good practice to unwrap/pack as efficiently as possible to gain precious texel density/pixel resolution. A good unwrap/pack is often overlooked/rushed by beginning artists, which is foolish as it is a huge factor in final quality especially wit game assets.

The islands don't have to be facing the same direction(unless baking lighting or other directional effects) In older 2D texturing workflows it was important to arrange islands logically and facing the same direction for ease of texturing, but not so much in SP. There is a strange viewport bug in SP, though, that shows the seam on islands connected by a UV seam, but facing different directions. It will be fine in UE4/Unity/etc though.

Excellent answer, thanks for the heads-up on that SP bug, If I didn't knew about that I would've been stuck in a loop trying to fix that seam in SP when it is totally fine in Unity/Unreal.

musashidan

You're welcome. On the last project I did in SP that bug was driving me crazy so I just ran a test similar to the one above to make sure it was just an SP visual glitch. There was another SP glitch before that one that showed bad triangulation due to the mipping algorithm, even though the mesh might be perfect in UE4/Unity. So I'm always on the lookout for bugs in SP like this. You can save yourself a lot of f^^king around by just running little tests to your engine to make sure it's all good there.

HAWK12HT

Nothing wrong with your layout other than (my personal view) that shorts you can align like shirt too, think of it as being hanging on shop floor via hangar you see them straight. Even though with all relax they fall into a curve shape however having them straight will be a life save if and when you wanna do manual texting, grafiti or anything that would require it to be straight like a tileable fabric pattern it will look off unless you play around with texture rotation value to align it with short but then you cant use same on shirt due to rotation value so you ll end up duplicating it thus making a lot of layers in SP.