See-through hair textures?

Hi everyone,

I've worked with Photoshop for years, and have been on Second Life for a while. After being on for a good time and getting to know the building, the controls, and lingo of SL that we all must learn. I think I'm at the point where I want to start making things for myself, or to sell. Looking over things, I was gonna make something simple. Clothes, It's good and wasn't really that hard.

However, lately I aimed at making "prim" hairs. Not fully prims, but with the whole torus tapered bit. Anyhow, I made three textures. Also I did follow that hair tutorial, with the skirt script and what not, but I didn't like the texture and made my own/went about it my way.

The three textures consist of this:
1. The hair textured stitched together on all sides
2. Hair texture with the alpha channel of it being "cut" and fading.
3. A bit like 2 but more "stylish" and looks more like "chopped" up hair rather then a loop.

Everything was going good until I noticed when I was making the hair, some of the prims and torus shapes with the hair texture "disappear" and show the shape behind it. Or you can see through one texture and see the other. It's a very strange thing to explain, hopefully someone knows what I'm saying. I got curious and took out a prim hair I own and took it apart, it was pretty much made up of the same exact thing, with the same type of textures. So I don't understand why mine are "invisible" and what not.


Any help would be greatly appreciated, thank you.

Hi Jackal!

Welcome to the famous Alpha Sorting / Alpha Blending issues.

Yeah, we all know exactly what you are talking about. It's an Open GL thing, and it's likely to happen, from some angles and at some times, whenever you have one image with transparency in front of another one.

It's all over SL, and no, it's not a bug, it's the way Open GL works, and no, there's nothing that the Lindens can do about it.

For more information about what is going on, and why we're not likely to see a fix until computers get much more powerful than they are now, take a look at http://www.opengl.org/wiki/Alpha_Blending

What can you do about it?

There are several things that people do, with hair.

One is to make it all full bright. That will keep the sorting issues from being as noticeable, with the side effect of giving you glowing hair at night.

One is to use the transparent prims sparingly, and use mainly opaque ones (24 bit) behind them.

Some people just ignore it, since it's everywhere, and make the hair however they want to make it.

People who make more hair than I do will probably have more suggestions.

Sorry that I can't tell you "Just do blah, and it will all be perfect!" I really, really, really wish I could. But I can't.

Hope this helps you understand, even if there's no fix,

The best hair that I have seen uses the 32-bit textures only where absolutely necessary, and uses 24-bit textures for most of the hair.

Once the hair is linked, the sorting glitch isn't quite as bad as when you're placing pieces together to make the style.

Please, DO NOT USE FULLBRIGHT FOR HAIR! It makes you look like you used radioactive hairspray, and you will sell FAR less of that style if it always glows in the dark, unless it is strictly a "Punk Rocker / Raver" style that is *supposed* to glow strangely.

Thanks to both of you for your responses. Yeah, the full-bright work around didn't seem like a good idea in the first place, as for the 24-bit textures. I've been using 32, for everything. Will lowering it to 24 reduce this problem?

Also, I heard that having PNG textures will also interfere and "glitch", do you know if this is true? Also if it is, which file-format is recommended? (for textures that have no alpha or transparency)

Anymore help is appreciated,

thanks again.

I always just turn the full bright off, as soon as I get the hair. Hair really needs to be copy/mod, in any case, so that people can get it to fit their own heads.

Using 24 bit textures will totally eliminate the glitch, since they don't have the problem. Of course, it will also make your hair look solid, which is why it's a good idea to just use the 32 bit on the edges, and not put 32 bit on top of 32 bit.

Yeah, if you're using 32 bit throughout, the effect will be.. ummm.. unpleasant.

It doesn't matter in the least what format you use to upload the textures, since they're all translated to jpg2000 during the upload process.

That said, there are a couple of things you might want to know about .png, especially if you're using Photoshop CS or higher.

First, you need to flatten your image before you save it as a .png, or PS will automatically add an alpha channel, at least in PS CS4 (which is what I have to test it with.) In other words, you'll get a 32 bit texture, with all the alpha sorting issues, even though you won't be able to see a speck of transparency.

Secondly, although .png does put the correct color in the transparent pixels in my tests, there have been reports by people I highly respect that in complex transparencies it can leave some haloing artifacts. You don't want that.

Personally, I recommend using .tga. Especially for textures with no transparency, 24 bit .tga is the way to go, IMHO.

Even if you are using transparency, I recommend .tga.

Alpha channels are really quite simple to make and easy to use, and give you much more control over the final transparency (or not) since it's simple to make them either 24 or 32 bit. You can also make an alpha, and then not worry about it while working with the rest of the texture.

I think of .png as the "quick and dirty" solution and rarely use it, unless I just want a fast test of something, on the beta grid.

Hope this helps!

Thanks a lot Robin. You've answered all of my questions. I'm a graphic artist/Photographer, and mostly work with PNG/JPEG/RAWs. Which would explain why I picked the "quick and easy" solution.

I'll be sure to re-upload my textures as a TGA and 24 bit. You seem to know your stuff so I don't have any doubt.

Thanks again.

Hey, I took the advice of everyone. Though I'm having a problem with the TGA files I'm using Photoshop CS3, and when I save the TGA with the alpha transparency at 24-bits, but the transparency disappears. I change it to 32, and it shows. What should I do?

That's actually OK! That is the difference between 24 and 32 bits, the 32 has alpha and 24 only has RGB.

Sure there is. They can dump Windlight. That won't eliminate Alpha blending problems, but it will reduce them significantly... the problems became massively worse when they introduced it. It's almost like they went from Z-sorting by the poly or face and went to Z-sorting by the whole prim.

Ah, it does seem a bit frustrating. But I guess I'll get used to it with practice. Thanks everyone for clearing up all my problems.

Use 24-bit for what you called a type 1 texture, where the hair is seamless edge to edge in both directions. Use 32-bit for textures that have to be partially transparent.

Example - A simple pony tail style:

24-bit textures for the majority of the hair on the head before the binding. Toruses mostly.
24-bit textures for some of the hair in the pony tail right behind the binding. Toruses mostly.
24-bit textures for the scarf or tie binding the hair into a pony tail.
24-bit flexi cones for about 2/3 of the hair hanging down in the pony tail.

32-bit hair texture on torii for the bangs, and for some wisps along the sides of the face.
32-bit hair texture on flexi box shapes and cone shapes and for most of the rest of the pony tail.