Hey guys, so during last September's monthly contest I noticed a few requests for help on hair items, and I've also gotten some requests and interest in seeing how I did hair for my recent pieces. I've put together this small tutorial which hopefully will show just how easy sculpting hair is for dota 2 characters. I'm not a particularly good sculptor myself, and I gathered these techniques from a variety of tutorials across the internet over the course of September. My intention is to compile and present the techniques I've come across in a single simple tutorial with the help of the only Dota 2 character deserving of such gorgeous hair.
If you're interested in any great supplementary tutorials, do check this one for painting hair in photoshop by Linda Bergkvist - I use it as a sort of theoretical basis to how I approach hair in 2d and 3d: http://www.cgsociety.org/index.php/CGSFeatures/CGSFeatureSpecial/tutorial_how_to_paint_realistic_hair
I personally use Modo (modeling, texturing, UVs, retopo) and Zbrush (sculpting) for my own work, so I'll be using images from both to demonstrate the techniques. However I understand that not everyone has access to such software, so where applicable I'll mention tools that do the same thing in Blender for modeling and sculpting where relevant. I've tested these Blender tools to make sure that they do the things I'd want them to.
My workflow goes something like this:
With hair I find the main worry is getting a nice shape to the sculpt base. Once you have that giving the hair texture is quite easy and fun. Because of this I like a more constrained approach to simple hair pieces like my CM item - I model them out with polygons or subpatches, usually starting with the edges of the hair and then filling in the inner polygons once the rough shape of the hair is visible.
I use subpatches (subsurf in blender) to get those smooth edges, though you can use flat polygons too since you can smooth it all out in Zbrush or the multires modifier in Blender anyway. To take advantage of this method, you want to get the shape and the border regions which separate your hair from your head model absolutely right - those are the bits that I find hard to do in sculpting. In particular you'll want to get the edges (spikes etc) of your hair in place during this phase.
Blocking the shape out like this in polygons works well if you already have a specific concept and shape in mind. You can have your concept in the background too to help you maintain your concept's shape. However for the more complex hairstyles it can be painstakingly slow. I'll get to those later.
For those who would like to look at what the sculpt base I did for this tutorial looks like, here's an image:
Once you have your sculpt base, send it to Zbrush and divide it or put a multires modifier on it in Blender, and the fun starts. I like to split the object into subtools as well at this point so that I can sculpt on the hair separately.
For hair sculpting I uses several brushes. ClayBuildup (Zbrush) or ClayStrips (Blender), Smooth, HPolish (Zbrush) or Polish (Blender), Trim Dynamic (Zbrush) or Scrape/Peak (Blender) and Dam Standard (Zbrush) or Crease (Blender).
ClayBuildUp/ClayStrips lays down strips of material that when overlaid becomes a nice streaky texture. I start by using a large ClayBuildUp brush to lay down the rough shape of the hair and use the Smooth brush with strokes in the direction of hair flow to maintain the streaks.
Once I've smoothed them out, I reduce the brush size and repeat the ClayBuildup and smooth process again until I have sufficient detail in the hair. Do note that with my CM hair I stopped detailing at a much bigger brush size than what I used here - this one's just for demonstration of how it looks. Figuring out what sort of strokes look nice on hair is just a matter of practice and study. Looking at pictures of real hair helps a lot.
The HPolish/Polish and smooth brushes are a big part of what gives a lot of sculpts their really nice clean look. Having built up the hair using ClayBuildUp, I polish the hair until it looks nice and defined. The HPolish brush can be especially destructive to detail at bigger sizes and combined with the clay buildup results in rather flat looking hair strips. If you want a softer look look you'll want to use the clay build up together with the standard brush and use a small hpolish brush to avoid flattening some of the smaller detail.
(Note that after this point I decided to divide my model one more time since I needed more geometry)
If you need to break a peak into a flat edge you can also use the Trim Dynamic or Scrape/Peak brush. For Zbrush users Trim Dynamic can be used much like the HPolish brush to get that clean, defined look. However, it also tends to try to flatten areas more than the HPolish brush I find, and is more aggressive in that way. The Trim Dynamic brush might give hair sculpts a more dynamic look.
Once you have the polished hair you can use the DamStandard/Crease brush to return some of the lost detail and better define the peaks and valleys of your sculpt. Combine these brushes with the polish and smooth brushes to produce really tight, sharp edges. I think the trick here is to use this sparingly so that the whole head doesnt look overly defined.
If you've been lazy like me and haven't defined the edges of your sculpt base properly, you can add them using the clay buildup brush and hpolish in much of the same way that I've shown so far.
Cleaning the entire sculpt up is then just a matter of using all the aforementioned brushes and the Pinch brush to get the shapes you want. Voila, that's it. Simple hair. Here's what my sculpt looks like after I've been at it with a few rounds of dam standard, hpolish and pinch. In this case the hair is really flat because the sculpt base was made rather flat.
After this you take your sculpt, bring it into your favourite package for retopo and go on your merry dota 2 creating way. If you're having trouble with selecting hair colours, colour picking from the default textures is a really good way to start and ensures that your colours appear in-game somewhat close to the default textures.
These methods work pretty well for dota 2 style fur as well btw.
So... what if you wanted to do something a little.. crazier? In that case modeling the hair can get really tedious (especially if you know you could do it faster in sculpting). You can of course build off a head model and sculpt everything in from scratch, using a mixture of the methods I've mentioned before and snake hook brushes. Dynamesh and the Dynamic Topology in Zbrush and Blender respectively can be very useful for such a purpose.
Here's an example of a 5 min dynamesh sculpt straight on the invoker head:
However, I personally find sculpting complex hair from absolute scratch quite difficult to get right. So if you have access to Zbrush, there's another way. Which will come in the next post.