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Goraaz
11-28-2007, 09:34 PM
Hi

I'm uv-mapping a character right now and I need a bit of guidance when it comes to properly setting it up. I have decided to use a different uv set for the equipment of the character but the rest of the body is using the same uv set(same colormap, spec-map etc). Is it ok to place the head along with the rest of the body? I've seen some characters which have a specifically large texture map just for the head.
Also I'm using the same uv's for both sides of the body so the character is pretty symetrical.

Tell me if I've done this correctly so far.

cheers

zen
11-28-2007, 10:35 PM
Seperate UVmaps (and thus materials) are often used for character customization purposes. I.e. the player can choose a head, a upper body, etc. Other possibilities is to have skin/organic surfaces on one material and inorganic on another because of material/rendering differences.

If you are using symetry UV mapping, you will run into big problems normal mapping your character unless your engine supports flipping RG channels on the "bad half" to allow this. Normal maps for characters is pretty standard now.
Also, artistically in next gen you should strive to make your character *less* symmetrical. Slightly crooked nose, a scar on one side, asymetrical cloth folds, etc. I havnt seen symmetrical mapping on the projects ive been on for years.

JuddWack
11-28-2007, 11:14 PM
Unless your character has a gigantic head there is no reason to separate it onto another map and even then it's not necessary.

You could use separate maps if you don't have a great computer like me. Of course this is only useful if it is a portfolio piece only. My laptop just can't handle Photoshop with several layers of 2048x2048, but that's probably overkill anyway. 1024x2048 is tolerable but I'd rather separate it into 2 1024x1024 maps, for instance a separate map for the upper and lower body.

If your character is symmetrical I'd say you can get away with a 1024 for the character and 512 for the equipment, but some screen shots of what you're working on might help.

BTW, have you seen this thread:) (http://forums.cgsociety.org/showthread.php?f=39&t=566807)

zen
11-29-2007, 12:22 AM
Unless your character has a gigantic head there is no reason to separate it onto another map and even then it's not necessary.

You could use separate maps if you don't have a great computer like me. Of course this is only useful if it is a portfolio piece only. My laptop just can't handle Photoshop with several layers of 2048x2048, but that's probably overkill anyway. 1024x2048 is tolerable but I'd rather separate it into 2 1024x1024 maps, for instance a separate map for the upper and lower body.

If your character is symmetrical I'd say you can get away with a 1024 for the character and 512 for the equipment, but some screen shots of what you're working on might help.

BTW, have you seen this thread:) (http://forums.cgsociety.org/showthread.php?f=39&t=566807)

That's traditionaly good practice, but does not reflect "nextgen" character creation. Its not just about pixel resolution, its also about shader and material management. And normal mapping is the norm now, and they dont work with symmetrized UVs.

iSOBigD
11-29-2007, 01:56 AM
Symmetrical models work fine with Tangent Space normal maps in most engines. Local space is another story.

You can still overlap geometry just like before. It would be stupid to have less than 100% coverage on a texture and have to use 2-3 textures to get the result of one. It would be very inefficient (ie it would use 2-3 times the amount of memory for the same amount of detail and therefore slow down the game for nothing).

Normally people use one texture for the body and one for the head. Weapons and other things that can change can be different files. UT3 might use separate textures for different parts like arms, shoulder pads, legs, torsos and heads, but only because they're interchangeable...to some extent.

zen
11-29-2007, 03:42 AM
Symmetrical models work fine with Tangent Space normal maps in most engines. Local space is another story.

You can still overlap geometry just like before. It would be stupid to have less than 100% coverage on a texture and have to use 2-3 textures to get the result of one. It would be very inefficient (ie it would use 2-3 times the amount of memory for the same amount of detail and therefore slow down the game for nothing).

I hate to be a smart-ass but, no, they dont work fine. Ive worked with normal maps and perpixel shaders extensively.
The proper orientation of the UVs is necessary for tangent space normal maps. If you symmetrize the UVs, you are effectively flipping the normals on one side. While they might look like they work, i.e its bumpy and it renders, it will not light properly in accordance with the light vector.
The only way to have a properly rendering symmetrized normal map is to (in the material) mask the model on one side along the symmetry line and flip the RG channels of the normal map on that side. Otherwise youll have a model that only lights properly on one side.

When using normal maps, overlapping UVs is okay and a great way to save texture space, rotating is also okay. But flipping UVs is a big no-no.

Artistically..well, symmetrical models just dont look next gen-ish.

Goraaz
11-29-2007, 05:59 AM
Alright, thanks for the answers.
The reason I'm asking this is because I saw some texture images of the Gears of war characters and the character presented(Boomer I think) had mirrored UV's. I have however also heard that overlapping UV's is a bad idea, especially in Maya so that's why I decided to post this in this forum.
Here (http://www.goraaz.se/GameTrooper071129.jpg)are some screenshots of the character. Some parts of the body don't have overlapping UV's like the head. The arms, legs etc all have overlapping uv's.
I did a test before just to see how the overlapping uvs' normals would look if mirrored and it worked fine but I guess it isn't if it doesn't work in a game engine's lighting. :/
Still, would it depend on the game engine itself? Given that it worked for GOW?

iSOBigD
11-29-2007, 06:27 AM
Like I said, it depends on the engine. id's Tech 3 (Doom 3 engine) models generally don't have a lot of overlapping, but I'm 99% sure I remember seeing overlapping for hands/arms in Doom 3 and Quake 4 texture files when I played around with the editor. The UE3 engine (used in Gears, UT3, Area 51, Stranglehold, etc.) also has plenty of overlapping for anything symmetrical...like arm/legs. Generally only the faces on characters aren't symmetrical just to give them a more realistic look, but the bodies clearly are, so maybe you just worked with a more limited engine, zen.

I already mentionned why it would be a huge waste to not be able to mirror parts...why would anyone have to use two parts of a texture for two arms when they can just use one? Same for symmetrical torso/body armor.

Here are some screenshots from GoW and UT3 where you can clearly see all arms, legs and bodies are mirrored...you're free to look for other ones too. (watch the middle of the chest mainly)

http://www.gamershell.com/static/screenshots/8312/258298_full.jpg
http://www.gamershell.com/static/screenshots/8259/260696_full.jpg
http://www.gamershell.com/static/screenshots/8259/260695_full.jpg

zen
11-29-2007, 06:49 AM
I understand its possible of course, hence the trick i gave above to be able to do it. I've worked on UnrealED 3. Im very familiar with the UEd3 material editor.
I guess it depends whats more important to the art direction; mirroring UVs to allow higher res textures or unique UVs to allow asymmetrical models. And your not "wasting" by using unique UVs. In oldgen terms, yes it was heresy, but with current hardware making asymmetrical characters really adds to them graphically. On the project im on now, its really nice to see characters with no symmetrical cloth folds all over.

and just to make sure we're all on the same page; overlapping != mirroring. You can overlap UVs without necessarily flipping them.
Goraaz specifically asked about nextgen, so normal mapping was a must. That being said, unless you have the specified feature to make use of flipped UVs, youd better stick to unique UVs.

Goraaz
11-29-2007, 05:34 PM
Great. I guess I can go on with my current UV map then?

Thanks alot for your time.

JuddWack
11-29-2007, 06:11 PM
I think the point that everyone is trying to make is you can do it, but if you want to make a compelling human "next-gen" character it is best to not use mirroring UVs. If you do, try to at least break it up with some asymmetrical equipment, clothing, accessories, etc.

Also I think to say that "Normally people use one texture for the body and one for the head" is a bit inaccurate. I'll admit I've never worked professionally in the industry but I have looked at just about EVERY WIP thread and front page work posted on CGtalk in the past 3 years. I haven't seen much of this at all on characters aimed at current gen console and PC.

As far as having symmetrical bodies... You may have a point iSOBigD that a hand model would be the same, but the textures should be different for the same reason a head model is mirrored but doesn't contain mirrored UVs. You may want to add a tattoo, ring or a scar on the left hand and not the right.

Just do whatever you need to do to get the results you're looking for. It takes time to become a good character artist and you'll learn the tricks along the way. I don't think there's anything wrong with starting off with a symmetrical character. You'll learn a bit about normal mapping along the way and knock off a character real quick. In the future, I'd try to aim higher, which will of course take longer. Cool trooper btw.

Goraaz
11-29-2007, 11:33 PM
Thanks for all the tips and help, JuddWack.

In the future, I'd try to aim higher, which will of course take longer.

I don't understand what you mean by aiming higher here. Do you mean the UV mapping?

Also I think to say that "Normally people use one texture for the body and one for the head" is a bit inaccurate. I'll admit I've never worked professionally in the industry but I have looked at just about EVERY WIP thread and front page work posted on CGtalk in the past 3 years. I haven't seen much of this at all on characters aimed at current gen console and PC.

Actually we did use a seperate texture file for just the head on NBA Live 06. I think this was because they only had a few body models for all the different head models in the game. But then again I don't think it's what people normally do. :/

JuddWack
11-30-2007, 12:00 AM
What do I mean by aim higher? I guess I just mean not using mirrored textures. You're soldier guy is pretty cool, but I'd like to see some asymetrical detail, expecially in the textures. The model looks really nice though.

Ghostscape
11-30-2007, 04:03 AM
Actually we did use a seperate texture file for just the head on NBA Live 06. I think this was because they only had a few body models for all the different head models in the game. But then again I don't think it's what people normally do. :/

It gets done whenever you want to have multiple people wearing the same outfit - it's important to put all exposed skin on the same material so you can swap just the skin (IE ungloved hands or cleavage or assless chaps : ). It's much more memory efficient than having entirely unique characters while still individualizing models a bit more - seeing 5 guys in McDonalds uniforms that are identical except for the heads still looks a lot more convincing than 5 perfect clones.

Goraaz
11-30-2007, 04:19 AM
What do I mean by aim higher? I guess I just mean not using mirrored textures. You're soldier guy is pretty cool, but I'd like to see some asymetrical detail, expecially in the textures. The model looks really nice though.

Thanks alot. I'm asking this because they both seem to have their own advatages/disadvantages etc from what I've learned. Detail before symetry and so on...
http://img157.imagevenue.com/img.php?image=00857_928117_20070710_screen003_122_837lo.jpg
The character model closest to the camera has got to have at least 2k textures. I can't acheive that kind of detail with the 1k texture maps I'm using at the moment. Even though I'm using overlapping UV's it still looks a bit low-res from up-close.

Oh, btw, here (http://goraaz.se/Troop071024.jpg)is an older screenshot of the model with all the equipment etc. I guess it looks a little bit less symetrical this way? ;)
cheers

JuddWack
11-30-2007, 04:35 AM
You got some awesome modeling skills. Mind posting the textures?

AndrewRaZ
11-30-2007, 05:43 AM
The character model closest to the camera has got to have at least 2k textures. I can't acheive that kind of detail with the 1k texture maps I'm using at the moment. Even though I'm using overlapping UV's it still looks a bit low-res from up-close.
cheers

When I was in school, Mike Capps made a presentation to a bunch of students I was able to participate in. He told us that all the textures for all Unreal Tech 4 characters were all being created at 4k, because they weren't sure what the capabilities of next-gen hardware were going to be, and that they could always scale it down. I know for a fact that the textures in game are mostly 2k (I haven't found any 4k yet, but I haven't been through the entire directory of UT3 or GoW). I think they use the 4k textures for marketing purposes though. Some schools of thought say no to scaling textures down though, since you lose detail in the filtering.

I've essentially been told (in bits and pieces) by my boss that I was evaluated based on my portfolio, and that the in engine experience got me the job. That said, focus on making it look good. If it's a bit high for game resolution, don't worry about it, as long as you can show off stuff that has very smart decisions made for game limitations. So if you want to put some incredible detail in a 4k texture and show off some outstanding work, go for it.

blank
11-30-2007, 10:14 AM
Character Modelling 2 from ballistic publishing.

Shows workflow for Gears of Wars, flick through the Web page demo version on the web page to page 21-22 ish, and you can clearly see the UV layouts, 2x 2096x2096 textures one for head and arms one for legs and body.

It does say: Depending on the importance of a character, most UV's will be mirrored to provide as much resolution as possible etc etc

http://www.ballisticpublishing.com/books/dartiste/character_modeling_2/index.php


I got this book when it came out, very nice pictures in it and interesting to see some of the workflow used in Gears of War.

Espen
11-30-2007, 01:28 PM
I can only agree. Excellent book. The Gears of War part from Kevin Lanning will show you especially how to work effectively on a very high quality level. It's focused on a 3ds max to zbrush and back to max workflow, with normal map baking done in 3ds max. But most interesting are all the textures and wireframe shots were you can see that things are done without any tricks. They are just excellently executed.

When I do UV layouts for characters I have two 2048x2048 maps. One for head and hands and one for rest of the body. Hands and Face are most important to define the character of a person and therefore I would always give them more space.

This is my typical UV layout without mirroring UVs. On the left side is still some space for eyes, teeth and so on. Hairs get an extra texture with alpha channel. But there is no "best" way to do this. It all depends on your character and the needs of your game engine/game.

http://www.pointsnap.com/download/CGTalk/faces/uv_layout.jpg

Wouldn't it be great to post some other UV layouts here to show the variety fo possible solutions for this problem?

I tend to work without mirrored UVs as it gives you the best artistic freedom. If you need a more efficient and therefore mirrored layout, simply bake on half of your character into a new mirrored UV set. You can also decide to not mirror the face and mirror the rest only. If you have a character with a scar at one side of the face you can't use mirroring there. But if this character has a scar on his upper body you can't mirror the upper body. So the strategy also depends on the design of the character. If you see characters only from the distance you do not need a special texture for the face at all and you can put it all to one texture page.

Normally the rule should be: the more important a character is for the game the more it can be seen in closeups or cutscenes the more texture space it should get. But maybe that's just my rule. :)

Best regards,
--Espen

Goraaz
12-01-2007, 08:01 AM
You got some awesome modeling skills. Mind posting the textures?

Thanks, that's always good to hear.
The textures aren't finnished yet, I'm gonna do some occlusion renders and stuff first before I'll be posting the texture files. Oh yeah, I need to clean it up too. ;)

I do however have another screenshot of it if you're interested. It's located here (http://forums.cgsociety.org/GameTrooper071201.jpg).

Thanks!

Goraaz
01-10-2008, 05:59 AM
Guess I'm a bit late but the textures can be seen here, JuddWack;
http://www.goraaz.se/GameTrooperTextures.jpg

Thanks

JasonH
01-10-2008, 01:30 PM
Model looks great man, no issues from what I see. As far as mirroring UVs, it's one of those "6 of one, half dozen of the other" issues. Mirroring parts allows for higher resolution, but yeah, if you want asymetrical detail, then that is completely shot if you mirror. Good thing about soldiers is that they're usually pretty symetrical. Typically I like to plan ahead a bit and mirror as much as I can, but give spots that I've already determined need to be special their own UV space. Of course you can model in some asymetry, with things like ammo pouches or armor pieces attached to the arms and legs. You'll probably notice it the most in the chest and face, since the mirrored UVs come to an actual point in the center, so you'll have to plan ahead a bit with your textures if you want to do that.

From what your character looks like, you could probably have polygons on the front of the torso be asymetrical, and hide the seam where the armor pieces end (armor is GREAT for doing that, just have to make a few cuts in your low-poly mesh to accomodate that). That will help with things like patches and nametags that military uniforms have.

In the end it comes down to the importance of what the piece is. Asymetrical wrinkles on pants legs might look nicer, but the added resolution you'd get from mirroring them is generally pretty good too.

*edit*
Spoke before i saw the finished map (silly me). Looks pretty good and clean, I'm sure theres a lot of advice for one way or the other, but that looks like exactly the route i would take.

Goraaz
01-10-2008, 03:02 PM
Model looks great man, no issues from what I see. As far as mirroring UVs, it's one of those "6 of one, half dozen of the other" issues. Mirroring parts allows for higher resolution, but yeah, if you want asymetrical detail, then that is completely shot if you mirror. Good thing about soldiers is that they're usually pretty symetrical. Typically I like to plan ahead a bit and mirror as much as I can, but give spots that I've already determined need to be special their own UV space. Of course you can model in some asymetry, with things like ammo pouches or armor pieces attached to the arms and legs. You'll probably notice it the most in the chest and face, since the mirrored UVs come to an actual point in the center, so you'll have to plan ahead a bit with your textures if you want to do that.

From what your character looks like, you could probably have polygons on the front of the torso be asymetrical, and hide the seam where the armor pieces end (armor is GREAT for doing that, just have to make a few cuts in your low-poly mesh to accomodate that). That will help with things like patches and nametags that military uniforms have.

In the end it comes down to the importance of what the piece is. Asymetrical wrinkles on pants legs might look nicer, but the added resolution you'd get from mirroring them is generally pretty good too.

*edit*
Spoke before i saw the finished map (silly me). Looks pretty good and clean, I'm sure theres a lot of advice for one way or the other, but that looks like exactly the route i would take.


Thanks alot. This was the first time I ever tried on overlapping uvs for character texturing and it turned out pretty well(At least in my opinion ;) ). The best thing was that I was able to use higher res texture maps which improved both the normal map and the color textures.
Here is a montage of the character I have put together. These are all screenshots, I didn't bother using the hardware renderer in maya since I lost some details I considered pretty important. More important than the anti-aliasing;
http://www.goraaz.se/GameTrooper.jpg

I think I'll stick to my former UV-mapping technique in the future. The non-overlapping one that is....

iSOBigD
01-10-2008, 08:56 PM
That looks very good. You can't see most of the detail because it's a small render without all the nice filtering, but I'm sure the small things are nice too.

For your model I think overlapping things was a good choice, since the accessories make it look less symmetrical, although at that size, TWO 2048 maps are a little much. I guess it depends what the model's for, but if it's for an FPS, you'd generally need to use smaller textures when you don't see a close-up of the character (saves memory and gains performance :)), but if you wanna show off the model itself, those sizes should be great.

Oh and about those UT3 models...keep in mind you can customize them in-game and change their arms, legs, torso, head, etc. so they HAD to use different maps for different parts in order to be efficient. It all comes down to how you plan on using your model, of course. If you put it in an RTS, you'll almost never need textures larger than 1024x1024 since all the extra detail wouldn't be noticible in-game...and so on and so forth.

Goraaz
01-11-2008, 05:56 PM
Oh no.. I just realised that the textures aren't 2k in the montage. It's actually 1024x1024 like the texture map I showed you, of course. Gotta change that info. Sorry, people!

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