Alpha channel questions

[Smash Panda]

Hi I'm new to this group and want to see if you guys could help me with some questions I have about alpha channels. I have been through both of hell jumpers tutorials and I noticed that he touched on Alpha channels for a little bit. And now I want to see if I can learn more about alpha channels which still confuse me today.

Previously I tried to follow the old tutorial that hell jumper made. Everything was going smoothly until I had to export my texture with an alpha channel. I duplicated a RGB channel for the alpha channel then saved the texture as a targa with 32 bits per pixel. I looked at the saved texture and I found that it was partly transparent. Any blacks or grays have become clear. I noticed that this wasn't what happened in the tutorial which, is what brings me here today.

So I have some questions:

Why did my texture turn transparent? And how do I fix this? ( I asked this in the old thread as well).

Do weapon textures have to have alpha channels or is it only for paintable hats?

How are alpha channels used in phong mask lighting for models?

I am just mainly trying to figure out how to use an Alpha Channel for my weapons phong mask.

Any advice or comments on these questions would be great!

Thanks

[HellJumper]

Are you using photoshop or GIMP?

As the name implies, alpha channels are almost always used to control the transparency of a texture (hence "Alpha"). However, the source engine can use the alpha channel as a grayscale map for various things other than transparency (such as a phongmask, a selfillum mask, etc.). I'm assuming the transparency you are seeing is in Blender, right? If so, you can just ignore it-- this won't affect your model when you compile it in-game (btw, making weapons isn't exactly the best thing to do. Valve hardly ever adds weapons. We just got new ones, but that was the first time in a year they added weapons).

I can't recall how to disable blender from using the alpha channel as a transparency value because I never use that feature (I know that it does, but I've never seen this happen without actually activating transparency).

Weapon textures can have alpha channels. You can specify what the alpha channel will do in the .vmt file (for weapons you'll have to create the vmt manually since the in-game importer doesn't allow for weapons).

You said you wanted to use the alpha channel as a phong mask, so in your .vmt file, you should have the following lines:

"$phong" "1"
"$basemapalphaphongmask" "1"

You can further control this with other lines in the vmt file such as the following:

"$phongexponent" "30"
"$phongboost" "10"
"$phongfresnelranges" "[0.95 0.5 1]"

Anything black in the alpha channel will make that part of the model look dull, and anything white will appear shiny (with intermediate shininess being gray).

[Smash Panda]

Hey thanks a lot for responding! I am using photoshop CS5 to create my textures. This really helps my understanding of Alpha channels. I will just ignore the blender transparency then.

I understand that valve doesn't add weapons very often. Which is kind of sad since I usually see a few great weapon ideas in the workshop that dont get added. Anyway I was just making this weapon more for the experience and for getting through the learning curve of actually creating an item for the game. The next project I plan to do is a hat. So hopefully I will have better luck getting that accepted in game.

I also just want to say thanks for your tutorials. They have been an enormous help. I knew nothimg about 3D modeling and texturing before I watched your videos. For some reseason they sparked an interest in me to learn more about 3D modeling. Now I feel very comfortable modeling in blender and somewhat comfortable in photoshop. I learn more everyday and I just want to say thanks for getting me started. It has turned into a fun hobby, maybe even more some day.

[HellJumper]

It's always nice to hear that. Keep it up, and you'll surely get an item shipped in-game. You aren't the first person to tell me that they never had any modeling experience before watching my videos, and those very same people also have some (if not, many) items in TF2. Keep up the good work, and good luck!