So UV's Don't Need To Be In 0 to 1 Space?

Christian Cunningham

I am pretty confused. I thought in order for a game engine to read textures correctly they needed to be in the 0 to 1 space on the uv sheet. This guy made a texture atlas and they extend the border. How would this work in engine? What am I missing?

Skip to 10:00 and check it out. I understand if it was for a render it would be fine. But I am confused because these are for a mobile game.

https://www.youtube.com/watch?v=gyJKHmDAH2Q

m4dcow

This thread probably belongs in Technical Talk section, but UVs extending past the border is often used for tileable textures. The Coordinates just continue tiling outside of 0-1 space, it is also why you can offset overlapping UVs for baking purposes and still have them work.

Clos3d

you can stretch them to 2000000000 2000000000 if you want, is just really heavy on the vertex compression.

The more you extend your UV'S, the more blurry and less accurate it will be.

Is not something that should really bother your workflow, try to keep them as much as you can inside 1/1 of course, but no engine should care if you place them at 5.5

Clos3d

and yea, tech talk

passerby

That is providing that your textures in your engine arent sent to clamped

Justin Meisse

I moved this into Tech Talk

Clos3d wrote: »

The more you extend your UV'S, the more blurry and less accurate it will be.

I've never experienced that issue, is this something that comes up at crazy scales?

Laying out your UVs passed 0-1 is very important for environment art, that's how you tile textures.

At one point I was making complete zones inside of 3d studio max, I would select all the terrain that was grass, flatten map it (using the iron in textools) and relax. It was a fairly low spec game so I believe the scale was 256 pixels = 1 meter.

sargentcrunch

n/a

Ramseus

Ah, I always wondered what full precision uvs was for.

Justin Meisse

Ah, I never worked with Unreal tech - looks like there's one thing Gamebryo handles well!

ZacD

I think Unreal Engine just starts chopping off decimal places, if every vertex is to the grid, there shouldn't be much of an effect. UE does it as a performance measure, it's probably a bad thing gamebryo doesn't have an optimization option for it.

Justin Meisse

I don't know the nitty gritty about Gamebryo but it seems to be more geared towards very large worlds which is why it's so popular for MMOs and stuff like the Elder Scrolls games. The programmers never gave us any guff about how our UVs where laid out, just the usual stuff like keeping draw calls down.

throttlekitty

That makes me wonder how Gamebryo does that now, those UVs would be multiplied many times over with nested scaling, but I've never seen anything scaled so big where that happens.

passerby

ya one of those things that does happen, but with the amount of scale used for most, you wont notice any of the perscion problems

Christian Cunningham

Thanks guys. My college professor told me to never have UV's outside the borders.

Fingus

Ah, yeah. Rule of thumb: If someone says to never do something take it with a huge grain of salt. Unless they can give a good technical explanation.