UV layout techniques
polycounter lvl 18
Gents, I've been having some trouble figuring out the best way to throw down my UVs. Right now I'm putting the biggest chunks in first so that they get the most space, and then filling the holes in with the smaller bits... but I always end up with something like this:
Way too many gaps left! Of course I can scale up some pieces, but after all is said and done I think I spent more time than I really have to on it (spent ~7 hours unwrapping that plane).
What's your method?
Way too many gaps left! Of course I can scale up some pieces, but after all is said and done I think I spent more time than I really have to on it (spent ~7 hours unwrapping that plane).
What's your method?
Replies
I would say thats damn fine what you have right now.
You will always have some space in the UVs but this isn't a bad thing.
I notice some araes where different parts are too close toegther so when you try painting them in PS the colours will "bleed" together. The small bits at the bottom and the bits around the tail fin will suffer this problem.
To solve this you should leave 2 or 3 pixels between each part.
As for my methods of unwrapping,I try and group things where possible,for example on a plane,id try and keep the bits for the tail section in the same part of the unwrap,then the wings + flaps together, etc etc oviously there will still be smaller bits scattered around and put in whereever I can fit them but the idea is there,for me to know exacly what bit goes where.
The other thing I do is flatten map everything before moving things around,this will scale everything in the unwrap window and keep all UVs sqaure. It will also normally somewhat break up the model but I just use stitch to put it back together then if need be break it up again to suit my needs,whatever I do from then as long as I don't dramatically move indervidural polys or verticies the unwrap is straight and as sqaure as possible.
Hope you see what i mean.
good luck with the texture.
John
But that's going to be a bugger to texture, because everything is at an angle, making horizontal and vertical flips an utter bastard to do.
You want to copy and paste and flip as much as possible to save time.
Not only that, it generally makes it harder to paint any details since you have to think and paint at a slight angle which is usually really annoying.
Lazy UV mapping and wasting pixels is unforgiveable. But that isn't what I'm seeing here. It's clear you've done your utmost to squeeze every iota of detail that you can wring out of this UV mapping. You've got to call it quits eventually. I'd do some final minor tweaks, and then start painting if I were you. Most modelers would be darn proud to have made a UV Map that efficient.
I'd do some final minor tweaks, and then start painting if I were you.
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I *really* wouldn't do that If I were you coldwolf. This is far from being a good UV layout. I will stress strongly what Rick and MoP are driving at. By having so many UV chunks at angles you are *seriously* degrading the potential quality of your texture painting AND you are making the process of UVmapping and painting much more painful. Keeping things straight is *especially* important on a non organic model such as this, since clearly you're going to be painting a lot of straight lines.
Check out piors cow knight unwrap: http://www.pioroberson.com/modelpages/info_cowknight.htm
Note how hes using the free straight lines that pixel rows give him to help out with the detailing of the sword and armor. UVmapping that sword at an angle for instance would have been just plain silly.
And if he's really as concerned with optimization as he seems to be, its going to be incredibly hard to keep those larger pieces aligned to the horizontal or vertical.
I'm just starting out with painting, so I didn't think about the straight lines and stuff. But the problem I'll have with that is that modo throws down the UVs at weird angles to begin with, plus there's usually some distortion (however little it may be), so lining it up perfectly is nigh impossible.
Quick edit: I also keep in mind the edges, which provide me with a great guide for alignment.
Joke aside, I think you are misbalancing problems here. Sure its nice to have packed UVs, but if creates an angled layout like that it's just ... silly. You might say, "Hey I got more pixels available that way!" True, but a game engine will dynamically downscale the texture at a distance anyway, and it will become a mess because downscaling techniques don't like angled lines as mush as straight lines.
Also, it dosen't really matter if you are using modo or any other app - if it aint good, it aint good. I see many hull pieces on your layout that suffer from the automated UVrelax problem. Take that topleft piece for instance - It might sound great in theory, but in practice you want all these edges to be parrallel instead of slightly angled. That way if you want to add some line on that piece, you just paint it straight, period!
Ha well...
Think about disconnecting the wings and placing them facing each other so they form a box. That will let lay out the fuselage in straight rows. Also how much of those tiny pieces can be mirrored or sized down to a tiny 2px space so they come off as just flat color?
But a map this complex was going to be very difficult to paint anyway.
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So for that reason its worth making ones life *more* difficult?
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It's going to have diagonal areas one way or another.
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Yes, but thats reason not to minimize the diagonals where possible is it?
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If you divide the model along its axis, painting it diagonally isn't really much different.
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I beg to differ. If you cant get a UV line perfectly horizontal, painting it slightly off horizontal is a damn sight easier than painting it at 45 degrees. jeez, imagine trying to rotate and position a plane i.d number on the above map. F that.
The difference in art quality of games that use artists that go the extra distance with techniques such as these and those that dont is clear to me. I can literally tell which games utilize this UV practise and those that don't simply by looking at the game. MGS, WoW, yes. Oblivion, Gothic3? Um, no. I bet large sums of cash that both those products are littered with sloppy, diagonal UV's. I'm with pior. If a modeler handed me this to paint, *after* id caused him actual bodily harm I would not be painting this aircraft model.
rivet-lines (or what they are called) are pretty cool for aircrafts, and its much easier to paint straight lines in a 2d program and copy paste them and move precisely.
breaking the larger chunks down a bit, wont be too bad, as the plane naturally is made of pieces anyway, so seams can be hidden with mechanical joints and alike.
I am by no means a uvmapping genius, and you should probably listen to MoP, Pior, Vig and Daz before me. When unwrapping I tried to pay attention to a few things:
1) UV Space - Is each different part organized in an efficent manner and maintain proper pixel/texel density between the different parts.
2) Organization - Is it organized in a manner that if someone else had to work on this, or I came back to it years from now and forgot how I organized each piece, that it would be easily figured out. Each piece of the uv is near, or in the vicinity of other pieces that match up to the corresponding parts on the model. All the UVs for the weapon are in one section, wheels another, body another, etc.
3)Easy to Texture - How easy is it going to be for me, or whoever is going to paint the texture to do what they want with it with how I mapped it. Are they going to be able to paint straight lines easily, recognize where each piece is, its orientation, paint on letters or symbols properly, paint out seams, etc.
4)The Engine won't ruin it - pieces are spaced far enough apart from both borders and other pieces that when the engine mips it down to a different size that it doesn't bleed together into one mess of texture.
Again, I'm no uv-mapping genius or guru, so others will probably have more useful information to add or tear this apart with. But I hope it helps somehow.
www.uvlayout.com
Furthermore, you are mapping a plane, so you don't NEED one. Thats a lot easier to map than a nekkid character because nekkid folks don't have panel lines.
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To avoid this I'm projection painting it
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Don't. Don't try to think of special ways to paint it beucase it looks hard - it's going to be hard because you have made it hard for yourself. Just fix it:
Planar top, planar bottom, planar sides. break the wings off. It's a machine, planar map it all using the had edges of the machine and panel lines.
To be honest, I reckon I'd map that in 30 minutes. I'd also knack yer ballix if I was given that to paint.
I had 30min to kill so I rearranged the UV layout and even ended up with some extra space. It would have gone faster if I was working with the actual UV layout not an image, but whatcha gunna do /shrug.
I think by just detaching the wings you will save yourself a TON of headache. I would also detach the nose cone as there are always natural seams around the nose cones of planes, like rick pointed out. Where you detach the wings can be a natural seam in the planes metal skin. Or just make sure to paint the same color on both sides of the pieces. You can always copy one row of pixels on the end of one piece, paste and stretch it a few pixels onto the other piece. Also don't be afraid to flip piece and paint them backwards if it will help arrange them better. Obviously you might want text pieces facing the right way but not always a must. Also think about skewing pieces so that you can draw straight lines on them (like I did with the wings). Pieces don't always have to be 100% the shape of the model you can fudge the angles and most of the time no one notices
Some of the shapes are so small they will be just blobs of color so you might be able to save more space by having a few boxes like a color swatch and just place these pieces inside of them. Giving you more room to scale up bigger more important pieces. Since I didn't have the model I had no clue what pieces where important...
One last thing, (you know it won't be the last but whatever) if this is the UV layout for this plane and this plane is game art, you need to optimize it before you start playing with the UV's. There are bunch of wasted polys, I would wager a guess that you could shave 1000-1500 polys.
Rick, I need a seamless texture for this plane because I'm giving it a camo job, which will look like this:
Vig, that's awesome, thanks! Being a plane though, the wings are very important since it's the most visible part of the craft while it's flying. So I'll change it around for that, but otherwise I better line it up like that if I'm going to show the UVs on my folio... and I don't particularly enjoy a cock punch...
And yeah, that's the plane. I was aiming for ~6k to be honest, since that would be the budget for something like the UE3 engine, but you're right, that much really isn't necessary. I actually shaved off ~300 while I was unwrapping, and I could do a lot more if I put some real thought into it. I'll give it a shot today.
fix the uvs, paint the metal, add all the decals on a layer. With proper UVS that will be easy.
Then take it into your 3d package and paint on the camo - OR use a procedural material and bake it down in your 3d app.
Seamless is not distortion free rememeber - and it's easier to paint on a clean layout.
That plane has seams you just can't see them because of the angle of the shot and the res of the picture. The seams are always there regardless of the paint job. They never lay down enough paint to cover the seams. this shot clearly shows wing seams that could cover up UV detachment. I get the feeling you would rather stick with the layout you already have because of the time invested already. I totally understand that and at some point you have to cut your losses and move on. I would only re-unwrap and rearrange if you plan to wack a few 1k polys out of the model. I would keep these things in the back of your mind for the next model and move forward with this one the way it is just to keep the project moving forward.