Small UV question...

Liubei

Hey guys,
I was unwrapping my mesh when I saw several tutorials where the UV shell ratios were always constant, and the UV tile was also always very tightly packed. I'm not sure why, but I think that for my unwrap the only way I can pack my UVs tightly is if I scale some smaller parts up, and I can only get a constant UV shell ratio if I leave a bunch of space untouched. ( I guess it would have something to do with the disproportionate size of the blade compared to the hilt)
I'm wondering now if it's better to have a UV tile where the textures are not identically scaled, or to have them all scaled and waste UV space? (or maybe there is a way for have a constant ratio and have it tightly packed? Or maybe I should have two smaller texture files, one for the blade and one for the hilt? I'm really quite unsure of what  the best course of action is here.)

 Here's some images of my templates

Non uniform ratio for objects (+/- 20% max)

The uniform ratio template. I haven't laid them all out nicely but I think you guys can see what i mean.

I've read that UV ratio is key in game asset creation, which is what I'm aiming for, but I'm still a bit unsure about wasting so much UV space.
Any tips would be appreciated, thank you.

ryebot

I'm still a noob at this stuff, but I feel you on that temptation to use all your UV space for maximum detail. I'd throw a test-tile map on there just to see how it looks on the actual object? Having really detailed textures on certain parts of the model and not others could produce kind of a weird look, so consistency might be better.

I'd be curious what someone more experienced might have to say!

Cay

Looking at your picture I feel like there's a lot that could be done to make it easier. It starts with where you put your seems and how clean you unfold it.
Then just start with the bigger pieces and add the small ones in.. approximating how much space you'll need to fit everything in. Scaling shells is perfectly fine in my opinion as long as you don't overdo it. Better give important areas more space than wasting it. In the end it's just a puzzle, the advanced tetris without a time limit. There are automatic packing algorithms as well.. but I guess it helps to do it manually to understand what's important.

Synaesthesia

It also helps significantly to straighten out shells. If you need to paint straight lines, you'll be unable to if the shells are rotated. The large 45 degree shell would be a nightmare to paint if there's any panels on it.

Liubei

Thanks guys. I think I'm going to try to keep the scaled ratio tile, hopefully it will turn out well.

@ Cay. I think that my UV layout is probably inefficient as well. Most of the cuts I made, I was trying to follow the advice I've read about putting the seams where the hard edges are. It may be why I ended up with a large number of islands... but I'm not quite sure haha. I'll keep on trying to optimize further though, thank you.

Thanks for the tip about the straightening as well Synaesthesia. I am trying to keep my panels on the blade on different objects, so I'm trying to avoid the 45 degree problem this way. I felt like the increased texture space would be more beneficial in terms of cost/quality, as opposed to having some more geometry and a bit smaller texture space for the blade. I don't know which is better in reality, though. I'm not even quite sure if having different separated objects intersecting each other will cause problems or not, or if I should have kept all the modeled panels in a single mesh, or if I should have praised Cthulu and asked him to make my mesh for me.

Bek

non-square texture ratios are your friend.

kanga

I heard the word was to scale the smaller parts up. It would depend on who you are doing the job for I guess. I reckon the advice about avoiding slanted shells for painting on later is very good advice indeed.

Ausonian

Bek said:

non-square texture ratios are your friend.

As Bek suggested, you could do a 1x2 (i.e. 256x512) or even a 1x4 texture (i.e. 256x1024), where the blade shell is in vertical position, and the remaining space is filled by the other pieces. You'll be able to minimize the wasted space, without the need to scale the smaller shells (bad practice in my opinion).

Eric Chadwick

We have some good advice on our wiki about UV considerations.
http://wiki.polycount.com/wiki/Texture_Coordinates#UV_Tutorials

Also it's worth noting that if you're working on any mobile assets for iOS, they only support square textures there. Any rectangular textures will be scaled up to square, wasting memory compared to Android or PC. Only an issue though if you're developing assets for mobile.

Liubei

Oh man, I had completely forgotten about non-square ratios! Haha in retrospect its such a simple solution but I hadn't at all thought of it!
Thanks a lot you guys. I'm not doing this for mobile, so I'll be fine there. I had no idea that mobile only accepted square textures though, so thanks for that bit of info : )
It seems like scaling the shells is slightly debatable, but I think I'm going to try to keep them scaled identically with the non rectangular texture.