Are these UVs good?

Hayden Zammit

Hi everyone. Working on something for my folio at the moment. Was hoping some of you with more experience could let me know if the UVs I've done below are fine or if anything majorly wrong stands out.

I tried to keep shells that are going to be of the same material close to each other where possible, but in the end, it was easier to pack it all without doing that.

Do I need more space in between everything, or is this enough?






Thanks!

Brygelsmack

I would pack it tighter and just bake out a color map to make selections easy.

Joost

The space needed between shells depends on the texture resolution and tech of the engine.

http://wiki.polycount.com/wiki/Edge_padding



The way you pack your UVs will also be different depending on how you author your textures though. If you're doing it manually then mostly manual packing will be best. If you use DDo or some 3d painting app then there's not much point and it's probably most efficient to use something like Ipackthat.

Also I really like this workflow for manual packing http://www.polycount.com/forum/showpost.php?p=2047776&postcount=12

Yep again. My routine is a bit more specific, though. I move islands above, below, left or right of the 0-1 range based on whether they are:
major part(s) - these are the big, continuous islands you sometimes get which are very awkwardly shaped, but you maintain them like that to avoid seams. Since these are so big, they need to go in first and you'll fit everything else in around them.
rectangular the pieces are - these are the easiest to stack and should go in corners
minor parts - the usually numerous tiny pieces that you add right at the end to fill up gaps
unfinished - these haven't been completely unwrapped yet, or they are pieces that are very low-pri, so they could be scaled down.. but scaling down prematurely is a mistake. Even if that side of the object will rarely be seen, down scale any islands down unless there's a noticeable benefit to doing so.

Oh and try to straighten your uv islands as much as possible without causing too many distortions. It helps make your packs more efficient and will look better because the pixels align with the uv edges

Hayden Zammit

I would pack it tighter and just bake out a color map to make selections easy.

Tighter, eh? Okay thanks, will do. I wasn't sure how much space to leave in between shells.

Yeah, I'm going to bake out a color mask. Would you do that by just assigning different materials to faces in your high poly and then baking the HP to the low?

Joost

Hayden Zammit wrote: »

I wasn't sure how much space to leave in between shells.

This method works well. From the wiki:

Visual Packing Guide

If you want a visual guide when creating your UVs, one easy way to see the spacing is to use a checker as the background image in your UV editor, with each checker square set to the padding width.
For example to get a 4-pixel-wide checker on a 512x512 image, tile the checker image 64 times... if you calculate that the checker image has 2 checker squares across it, then the checkers bitmap should be 8 pixels across for a 512 image, and 8 pixels goes 64 times into 512, so that means it needs to be tiled 64 times across your UV square. Remember though, that if your UV space isn't square, then the checker tiling needs to be adjusted.

Hayden Zammit

Thanks for that link Joost. I think I'm going to get some base textures with DDO and then manually paint the rest in Photoshop.

I don't have Ipackthat, but I might get it for whatever I make next.

I think I followed most of the advice that was given in that link.

WarrenM

iPackThat would chew this up and spit out pure joy.

Hayden Zammit

iPackThat would chew this up and spit out pure joy.

Ah I've been tempted to get it. Guess I will. The fact that you have to go through Steam was holding me back, but reading the polycount thread for it again, am I right in understanding that if you buy it now through steam you'll get a non-steam license later on?

Hayden Zammit

Alright, so I bought Ipackthat and ran my mesh through it:



32% wasted space according to Ipackthat. What should I do in these situations? Just go back in and scale up more important parts? Give unique UVs to some parts on the other side of the mesh?

ZacD

I'd get rid of some of the mirroring, make sure the top parts aren't mirrored, because in an FPS view, you'd notice that easily. Also get rid of mirroring where you might have texture.

Basically you have a bunch of long parts, and not enough other stuff to fill the gaps, think of it like unwrapping a normal sword, there's no way it'd fill up the whole UV space on it's own.

Hayden Zammit

I'd get rid of some of the mirroring, make sure the top parts aren't mirrored, because in an FPS view, you'd notice that easily. Also get rid of mirroring where you might have texture.

Basically you have a bunch of long parts, and not enough other stuff to fill the gaps, think of it like unwrapping a normal sword, there's no way it'd fill up the whole UV space on it's own.

Okay, I'll make these changes.

I tried to give make some shells bigger and run it through Ipackthat again, but it doesn't want to seem to work once the shells have been re-sized. Down the bottom it says Nothing Selected, but there's no progress at all. If I click stop packing nothing happens either.

ZacD

I'm not sure exactly how to use all of the features, but I would just rescale the UVs in a separate application.

Hayden Zammit

I'm not sure exactly how to use all of the features, but I would just rescale the UVs in a separate application.

Maybe I didn't explain it well. I did rescale the UVs in Maya. Take a look at this test version. I scaled down that group of shells that I've indicated at the bottom. Then all of a sudden Ipackthat won't do it.
EDIT: Think I figured it out. Got something to do with having multiple UV sets.

Hayden Zammit

Okay, Ipackthat is pretty awesome:

FourtyNights

Oh gosh that color scheme really, really hurts eyes to look at. Sorry, had to.

peanut™

THere's plenty of unused space, stay focus and adjust everything so that only a small small portion is unused. (scale, rotate, stretch)

cookedpeanut

I'd like to pitch in here quickly, be careful when scaling uv islands independently of their respective connected parts. You'll find that the normal maps may come out slightly strange where a connecting point or edge has more uv space and therefore has a higher pixel density.

If you scale something, make sure to scale all the islands that connect to that piece? Does that make sense?

The last uv map isn't that bad, it just looks like you have edge-padding up quite high.

Hayden Zammit

Oh gosh that color scheme really, really hurts eyes to look at. Sorry, had to.

Yeah, it ain't the prettiest. Don't think I can change it.

THere's plenty of unused space, stay focus and adjust everything so that only a small small portion is unused. (scale, rotate, stretch)

According to Ipackthat, there was only 17% wasted space. I thought that was pretty impressive.

I'd like to pitch in here quickly, be careful when scaling uv islands independently of their respective connected parts. You'll find that the normal maps may come out slightly strange where a connecting point or edge has more uv space and therefore has a higher pixel density.

If you scale something, make sure to scale all the islands that connect to that piece? Does that make sense?

The last uv map isn't that bad, it just looks like you have edge-padding up quite high.

Yeah, that makes perfect sense. I was careful to avoid scaling like that.

The padding between shells is 16 pixels at the moment, the default in Ipackthat. I might lower it a bit. I also set it to keep a 4 pixel margin from the outer borders.

Also, replies from peanut, then cookedpeanut. Bizarre.

ZacD

You don't need an outside border margin unless you are using a lightmap or a specific engine that needs it for some silly reason. under 25% wasted is fine, some UVs will pack well, others might not.

WarrenM

According to Ipackthat, there was only 17% wasted space. I thought that was pretty impressive.

Yep! And the last step I generally do is to go through the smaller shells, the ones that could use a little more res and scale them up to fill in the holes. But 17% is not bad by any means ...

Mario is going to add this feature to iPackThat so it automatically takes the shells you tag as "scalable" or whatever and fill in holes at the end of the pack. But not yet...

Hayden Zammit

You don't need an outside border margin unless you are using a lightmap or a specific engine that needs it for some silly reason. under 25% wasted is fine, some UVs will pack well, others might not.

Ah, thanks for letting me know about the borders thing. I thought I needed it.

Yep! And the last step I generally do is to go through the smaller shells, the ones that could use a little more res and scale them up to fill in the holes. But 17% is not bad by any means ...

Mario is going to add this feature to iPackThat so it automatically takes the shells you tag as "scalable" or whatever and fill in holes at the end of the pack. But not yet...

Yeah, I'll probably scale em up like you suggest. Will be cool when that feature gets added. Pretty amazed by how good Ipackthat is. Do you usually group related shells so they pack near each other?

WarrenM

I don't bother with grouping but then I texture everything in Substance Painter, so the actual location of the UV shells is not something I need to care about.