How should I texture character's hair?

DanaosC

Hello everyone!
I decided to post as I believe here's the place I got the biggest chances of a good answer.

I'll cut to the chase, I want to texture my character's hair. Previously I was doing it by hand, meaning with PS I layed out the shadows, midtones and highlights and then make an alpha map. This time though I got so many hair strands (planes) and doing that would take A LOT. I imagined there should be another way.
Here are some shots of my character.



Here are the UVs of them (I also have some other stuff unwraped but detached them for the pic), not sure if that's the correct way of laying out hair.

As you can see painting them by hand would take hours and hours, I believe it's a waste unless there's no other way.

I am quite new to the 3D world so anything you have to say is really welcomed, thanks a lot!
Cheers,
-Dan

velesius

Hi! First of all you should reduce number of UV chunks, don't afraid to overlay them. There is no need to have dozens absolutely unique hair cards. Also, best looking hair you can achieve by using many (hundreds) hair planes (cards) with thin hair strands painted on them. This technique allows you to hide separate hair cards.

Makkon

Make your hair textures first, you only need a few variations. Map all your UV islands straight, and overlay them.

thomasp

having a few straight UV islands/hair texture variations like makkon said is the first step. also lay them out so they are facing in the same direction, root to tip. helpful to control highlight direction when applying a hair shader using anisotropic highlights.

DanaosC

Hello everyone! Thank you for the replies, I imagined I did something that would produce trouble.
I understand what you're saying and I'll definatelly do it in the future. Although, I used a hair strand Curve insert brush in Zbrush to make these, meaning i do not have exact control over the shape and polycount of the final "hair card".
I got that you suggested I make a couple of hair strands and then duplicate them and place them in new places, I did try that in the past but then I find it hard to place them to a new place, as the curve brush is easy when I just draw over the head.
Thanks again guys, looking forward to learn new tricks and tips.

a3D

Your workflow does not stop you from overlapping UVs in any way. Nobody said duplicating the hair strand mesh was the only way.

Michael Knubben

That's one way, but as others have suggested: just make a texture with a few strips of hair, and overlay the uv's on top of eachother.
And always google before asking, and check the Polycount Wiki! http://wiki.polycount.com/wiki/HairTechnique

DanaosC

@a3D To overlap a UV island, shouldn't it be the same? Otherwise it wouldn't fit. Even if I made them long squares like the guys mentioned, then overlapping non-same ones would make them stretched and I assume we don't want that. As I said I am quite new to this so feel free to correct me.

@Mightypea There are only a few hair tutorials out there and in fact I've checked the wiki, didn't mention anything I didn't know. I was actually wondering about the specific technical parts, like do you handpaint the hair or apply some real life textures? What about the Alpha map, what kind of brushes do you use in PS to make them. Stuff like that.

I'm currently trying out GMH2.6 and it turned out decent-ish. I'll upload the results later on this thread.

Thanks again guys, sorry for my inexperience!
-Dan

Eric Chadwick

I've checked the wiki, didn't mention anything I didn't know. I was actually wondering about the specific technical parts, like do you handpaint the hair or apply some real life textures? What about the Alpha map, what kind of brushes do you use in PS to make them.

Umm, no you haven't. Or maybe you did check the wiki out, but then failed to actually open the links to study them? I'm disappointed in you, it's all there Dan.

skankerzero

Hair is difficult to make look good, but super easy to make look bad.

A lot of the technical advice anyone could give you here depends on the rendering engine you'll be putting it through. You're going to have a ton of sorting issues if you don't get your rendering order of the plans correct. Especially if there are cards that curve around and have to render against themselves. There are things like choosing 1-bit alpha vs 8-bit alpha. What type of shader are you going to apply to it? Are you going to double side the geo through the shader or through the cards? etc.

You can overlap any uvs on anything. It doesn't matter if they have exact geometry or not.
You probably need about 5 unique hair textures. You can always bake ambient occlusion to the model verts to make the hair appear to have more variation and depth.

Personally I would lay out the hair texture first and fit my uvs to that. Keep the hair flow in the same direction. Generally roots to tip. I would use 8-bit alpha on the outer hair cards and the ones that break silhouette. Then I would use 1-bit alpha on the hair cards that hug the scalp.

There's a lot of advice that could be given, but we would need more context for the model.

a3D

Stretching is not a problem if you make sure the longest strand is not looking pixelated (has enough resolution) then the shorter ones will have better resolution once stretched.

Also you don't necessarily need to stretch. Just move the UV shell around on your hair texture and find the best placement and size for each hair strand.

DanaosC

@Eric Chadwick  Oh Eric I did mate :P My main issue wasn't how to make the polygons but rather how to texture them. One of the tuts on there suggested I make lots of thin hair to make the alpha map which I found absurd. Although I guess it's because I haven't managed my hair cards correctly, will surely go at it differently in the future.



Thanks a lot for the tips @skankerzero @a3D , I'll definatelly try the overlap method next time.
Here are the results of the current model, took me some time to get it "right", I believe it's acceptable for now, onto the next work to level up.

You can also check it in the online viewer if you want to ^^
http://www.danaosc.com/Marmoset/Liona.html

Cheers everyone, thanks once again and have a great day!

DanaosC

Quick question.
If I want to lay my above UVs of hair like so:


How should I do it? I doubt it's done manually, at least I hope not :P 
Edit: I know there's a way to do in Maya (as the tutorial states) but i was wondering if we can do it in 3ds max too.

Makkon

I was about to say, I know how to do it in Maya, but Max probably has some robust tools in there.

If you haven't seen this tutorial already, it's rather high level but it might answer some big-picture questions for you.
http://www.3dartistonline.com/news/2015/04/how-do-i-create-real-time-hair-for-games/

Also, if you end up doing another character like this again, feel free to try out my own zbrush hair strip brush:
http://tmblr.co/ZrZZpw1v7TVoP

DanaosC

@Makkon Hey man, yeah that's the tutorial I referenced in my last comment This is how I am going to do it in the future but it just sucks that you can't unwrap the hair cards like so in 3Ds Max. But oh well, back and forth it is

Also I am super thankful of the brush! I'll try this one next time instead of my old one. Have a great day mate!

Eric Chadwick

You can unwrap them like this in Max. Look for Spline mapping in the Unwrap modifier. Or you can try a simple Planar projection then Relax the hell out of it, then use the Straighten Selection tool in Unwrap. 
http://help.autodesk.com/view/3DSMAX/2016/ENU/?guid=GUID-9E98AEAC-F06F-4FAD-9091-DCD30AC9BB26

DanaosC

@Eric Chadwick 
Woop, how about that, looks very nice although giving slightly different results than Maya, meaning I need to kind rescale but awesome nonetheless, thanks a lot mate!

skankerzero

I just bring the hair cards into UVLayout and press R.

DanaosC

@skankerzero
I've never tried out UVLayout, does it give the result as in the pic above?
We have a different app for each thing and I kind of dislike that but I guess it's better have apps excelling at stuff Will give it a go.
Cheerio~

skankerzero

I use UVLayout because it's hotkey driven and speeds up my workflow. 

Different software for different things for sure, but with UVLayout and iPackthat, uvmapping in Max seems so archaic.