specular mask in alpha channel

Loren Broach

Hey guys I'm doing another art test and they are asking for a 768x768 diffuse with a "specular mask in alpha channel". What exactly are they asking? I've never heard of that before.

Jesse Moody

basically you are making a mask on what will be the specular and what will not and how much depending on the shade of gray / black you use.

Loren Broach

oh ok, but is this specular mask in the alpha channel of the .tga file? or does the it go in the opacity slot in the material editor? I'm just not sure where the specular mask goes.

Jesse Moody

so i take it this is for unreal 3 then. Well then this spec mask is probably going to go into your spec power slot and your spec mask will go into your spec map slot.

Rick Stirling

I assume it's just a way of storing the specular texture in the alpha channel of the diffuse map. This means that only one texture has to be streamed into memory rather than two (even though the size in memory would be the same).

So, I *THINK* that you have a diffuse texture, and an specular map, and it's just a storage method.

You could ask them to clarify.

Eric Chadwick

Who uses 768x768 ?

Mark Dygert

Save the tga with the spec map in the alpha, then in 3dsMax, put the tga in the diffuse slot and in the specular map slot, then in the bitmap parameters for the spec map slot, change the mono channel output to be "alpha".

Like Rick said its just an easy way to save file/memory space by including it in the alpha of one texture rather then in two separate files.

Loren Broach

I'm doing an art test for Bungie, they use 768 apparently. Thanks for the help guys! I'll try your suggestions.

odium

Bungie? Which means its next gen, which doesn't matter, power of 2 has been the standard for years now.

Ask them before you do any serious work if that means a 512x512 and a 256x256, or if they really mean a 768x768. I find that a bit silly to require that res, and its probably why the art in the Halo games is never up to much.

Mark Dygert

Bungie is weird that way. I almost took a contract doing props for Halo3 (would have had to quit my FT job for a 3mo contract yuck). I did their art test just for fun.
Their texture requirements where funky.
Dimensions: 10’h x 10w’
Textures: 384x384 + 64x64 tiling detail metal texture
Poly Count: 800 or less polys

I got the impression that they wanted two textures, and that the first one needed to be 384x384 and wasn't a max pixel budget for me to spend how I liked. But I never bothered to ask, since I turned it down.

Jabberwockxeno

Sorry for the necro.

Interestingly enough, I came about this thread because I'm working with some halo assets I want to import into a nifty program called space engine, that also requires the specular map be in the alpha channel of the diffuse. I guess bungie likes storing the speculars that way!

The issue is, I don't know how to do this, particularly since I had to bake the multi/sub object mat into a single diffuse map for space engine.

Eric Chadwick

If you're using assets from another game, beware copyright infringement.

But if it's just for educational purposes, use your image editor of choice to make an alpha channel, and put the specular in there. Are you using Photoshop or Gimp?

Jabberwockxeno

Eric Chadwick wrote: »

If you're using assets from another game, beware copyright infringement.

But if it's just for educational purposes, use your image editor of choice to make an alpha channel, and put the specular in there. Are you using Photoshop or Gimp?

I figured the best way to learn stuff would be to look at assets from games and mess with em, so yes, it's for educational purposes. That, and I want to see what halo ships would look like in space engine. So a bit of personal use, too, I guess.


GIMP.

I already tried to do this once, but it's not as simple as pasting the image data on the alpha channel, or if it is, I'm not realizing it.

A step by step set of instructions would be appericated.

Eric Chadwick

I'm not a Gimp user. A Google search didn't work for you? I searched for "Gimp paste alpha" and this was the first hit. http://www.sas1946.com/main/index.php?topic=9790.0 Seems like it has the steps pretty clearly listed.

Jabberwockxeno

Eric Chadwick wrote: »

I'm not a Gimp user. A Google search didn't work for you? I searched for "Gimp paste alpha" and this was the first hit. http://www.sas1946.com/main/index.php?topic=9790.0 Seems like it has the steps pretty clearly listed.

I actually did google it, but not the right words, apparently. Thanks!

Jabberwockxeno

Well, that didn't work, but that's the instructions everybody else gives too.

Hmmm.

dissonance

c.buliarca

Hi Keen, you can use my script for photoshop to automatically save your tga with some other group as alpha channel.
http://www.creativecrash.com/photoshop/downloads/actions/c/bcm-panel-save-each-main-group-as-tga--2

passerby

check this out it should help with this. http://felixschlitter.com/snippets/quick-save-maps