Is it ok to leave UV's out side of the render area?

poopstick

Basically I have a building that is part painted texture and part tiled texture(walls)

I've no need for the unwrapped walls to be on the texture map as they won't need painting, all I need is for them to be all proportionally unwrapped so that the tillable texture applies correctly, like this http://prntscr.com/8sn6su

At this point I don't really know what is best. I can either plop the wall uv's right in the centre of the map overlapping everything, or I can just put them outside of the rendered area.

I mean the outcome is completely fine whichever way I do it but I'm wondering, is there something I'm overlooking, or is it perfectly fine to do this?

http://prntscr.com/8snc4f

m4dcow

Yes it is fine to leave them outside 0-1 space.

JedTheKrampus

To clarify, it's fine to do that unless your renderer sets the behavior outside of the 0-1 space to some mode besides repeating the texture. See the documentation on glTexParameter here to get a better idea. For most renderers you have to go out of your way to do this, so it's really not something to worry about unless you're also using some kind of weird multi-tiled UV texture.

poopstick

Thanks guys, would there be any difference in effeciency depending on where your UV's are outside of the 0,1 space? or how big etc.

throttlekitty

Nope, they're just numbers, we do it all the time for tiling environment models. So theoretically the only thing you could break would be to exceed whatever data type your target engine uses, but you'd probably get an error on export. This would also be ridiculously gigantically scaled up and not something you'd be likely to run into.

sprunghunt

poopstick wrote: »

Thanks guys, would there be any difference in effeciency depending on where your UV's are outside of the 0,1 space? or how big etc.

Some engines use a kind of compression on UV coordinates which means if you have huge UV charts then you'll get inaccuracies (stretching and warping) at the extremities. Of course the best way to test this is to check your work in-game.

Quack!

sprunghunt wrote: »

Some engines use a kind of compression on UV coordinates which means if you have huge UV charts then you'll get inaccuracies (stretching and warping) at the extremities. Of course the best way to test this is to check your work in-game.

I want to second this to drive it home.

As you get a certain number of units away from 0-1 you can start to lose floating point precision, depending on the engine. I have encountered plenty of wobbly PS1 style texture artifacts due to placement relative to the 0-1 space.

poopstick

Fortunately I've not seen any graphical anomalies, apart from in my hasty unwrapping. Thanks for the help guys, surprised that I've never known this before. I've got some reassessing of models to do :P

EagleTopGaming

The one thing I found is Substance painter does not like it when you do this. Though it works fine in Designer and Unreal.

huffer

It also doesn't work well with Mudbox, as far as I know, you can't paint over a shell that sits even a tiny bit outside 0,1.