As the "Linden Folk" most responsible for how the avatar hair works (or doesn't), let me be the first to apologize to those having difficulty getting their old hair style back in the current release. There were a lot of requests for longer hair, and unfortunately changes to the hair object to support that feature means that certain hair style slider combinations yield different results from earlier releases. (can you say "beta?"
Fortunately, if you play around with the hair slider combinations enough you should be able to get any of the hair styles you had before, plus some new styles that were previously impossible.
If you play with the hair sliders for any length of time, you'll realize that finding a particular hair style is more art than science. And the fact that your head shape is independent of your hair shape means there's lots of combinations that are just going to look... wrong. So, here's a few tips for all you frustrated hair wranglers out there.
1. Think of the hair object more as a lump of clay to be sculpted into shape as opposed to tufts of hair that need to be trimmed or lengthened. The sliders allow you to push and pull different areas of the hair, as if you were sculpting it's shape. The exceptions are the "fringe" sliders which do, in fact, control the length of tuft-like fringes of hair.
2. Because the hair sliders are additive, it's possible to paint yourself into a corner. For example, if you crank the hair "volume" slider to 100, and then chisel away the hair with a combination of other hair sliders, you might "lose" the ability to grow the hair back in a uniform way. The solution is to keep the volume slider at 50, sculpt the hair into the style you want, then as the last step adjust the volume up or down to fine tune how close or far the hair is from your skull. If a part of the head goes bald before the other parts, then you know that the hair length in that part isn't even (relative to the skull). You can then adjust that area with some of the other sliders, and adjust the volume again as the last step. This would be a way to create a hairstyle that is very close to the skull without bald spots. In general, the more globally the hair slider affects the hair, the more careful you should be about using it. Imagine cranking the spikey hair up to max and then trying to "de-spike" your hair using the other sliders! It can't be done. And trying to subtly change the shape of your hair AFTER you've added spikes is more difficult than saving the spikes for one of the last steps.
3. If you do paint yourself into a corner and really just want to start from scratch, try using the "randomize" button to generate a baseline hair style. The hairstyles generated this way are fairly conservative, and may even result in bald spots depending on the shape of your avatar's head, but the sliders are at least reset to more editable (less extreme) positions.
4. If you want a really close-cropped looking hair style (shaved head, buzzcut) here's another posssible route: Shrink the hair volume so you are bald, then paint the hair as a texture on the "Head Tattos" layer. This is somewhat involved, and requires use of an external paint program, but I'm sure there are some enterprising texture artists out there up to the challenge. We will also be releasing a head texture template soon that will make creating these types of textures easier.
5. Don't be afraid to change the default texture of your hair to something completely different. The default hair texture uses transparency around the "fringe" areas of the hair to simulate the whispy ends of some hair styles. You could use a texture that didn't have a transparency channel at all, and this would give the effect of having thicker, straighter bangs, for example. You could probably even simulate a roman helmet using an appropriate texture on the hair object.
The idea behind the hair object is to give Second Lifers as much flexibility as possible to create many different hair styles. The downside of this approach is that finding the right combinations of sliders to achieve a particular effect for your particular avatar can sometimes take a lot of tweaking. The upside is the freedom to create truly unique and interesting hair styles. Good luck, and have fun!
-Xenon
