Alpha Textures

One more example of texture blends..
This is a screenshot of the detention cells on the Morpheus.
The glass effect I wanted here was a bit different.
The cells themselves are quite well lit whilst the corridor is a bit on the dark side.
I wanted to get the effect of the cell lights reflecting off the glass windows.

The same dirty window texture was used but this time…..
The texture flags for Colour and Alpha were set
The Base Texture blend mode was set to Additive.
The Additive blend mode lightens any textures placed behind the glass.
So this blend mode appears to make the glass look a lot lighter, but it’s a trick, what is actually happening is the textures BEHIND the glass are lightened, not the glass texture itself.
Note how the wall texture, when viewed through the doorways remains normal.

[img:2dlwjbne]http://img508.imageshack.us/img508/831/glass1hd0.jpg[/img:2dlwjbne]

Using alpha textures in our paint app is something that really needs a tutorial of it’s own.
You can create an almost endless number of effects this way.
When I get time I’ll see if I can write one, it involves a lot of trial and error but it’s worth the effort.
Here’s an example….
The image on the left was how the face for this figure was originally painted.
I wanted to get mote detail into the skin texture.
So in Photoshop I first made a copy of the original texture (The one on the left)
I created a Normal Map of the copy and desaturated it.
Bumped up the contrast
Copied it back to original as a new layer.
And changed the layer blend mode to Soft light.
I then erased everything from this layer apart from the face area.
I ended up with the image on the right
This is still a bit WIP…I’m not to sure about it but it’s growing on me.

[img:20j5sovr]http://img519.imageshack.us/img519/4120/atexture2rx4.jpg[/img:20j5sovr]

Thats about it really…it really is an interesting subject.
Please add any of your own ideas, I’m always interested in learning new tricks with alpha textures.

Bazza

Wow! quite a mini tut, Bazza.Thanks. One thing I am not sure about – which buttons to activate in 3DC, e.g. for transparencies, I select translucency map, but what setting on the tanslucency function? I read somewhere to select one for opaque and two for transparent, but the increments are up to 100, so what do the other 98 positions do?
Cheers, Fender <!– s:) –><img src="{SMILIES_PATH}/icon_e_smile.gif" alt="" title="Smile" /><!– s:) –>

Hi Fender
Sorry I didn’t make this clear.
I depends what you are going to do with the model.

If it’s for a train sim you would need to check what transulancy settings the train sim requires for translucent textures.
Maybe one of the train sim guys could comment on this.

For models that are going to export to another app or 3D engine I always use the following settings….
Diffuse = 100
Ambient = 0 (but I can’t get it below 1 in V7)
Specular = 0
Translucent = 0

I can make a adjustemants to the translucent setting in either Giles or Blitz, so I never need to use it in 3DC.

Bazza

Excellent tutorial. This will help a lot of people understand alpha better. Thanks.

Thanks…it took a while to put together and I really only scratched the surface, I’ll do some more when I have time.

It may take a while though…I’m messing with lightmapping animated objects thanks to some code from Fredborg.

Remember to add any of your own ideas to this thread if you have any.

Bazza

Bazza, thank you very much for this! Clarifying some things which have been totally mysterious to me … <!– s:) –><img src="{SMILIES_PATH}/icon_e_smile.gif" alt="" title="Smile" /><!– s:) –>

[BLOCKQUOTE class=’ip-ubbcode-quote’][div class=’ip-ubbcode-quote-title’]quote:[/div][div class=’ip-ubbcode-quote-content’]Originally posted by Fender:
Wow! quite a mini tut, Bazza.Thanks. One thing I am not sure about – which buttons to activate in 3DC, e.g. for transparencies, I select translucency map, but what setting on the tanslucency function? I read somewhere to select one for opaque and two for transparent, but the increments are up to 100, so what do the other 98 positions do?
Cheers, Fender <!– s:) –><img src="{SMILIES_PATH}/icon_e_smile.gif" alt="" title="Smile" /><!– s:) –> [/div][/BLOCKQUOTE]

Sorry, I didn’t reply to this one.

In general, the translucency setting is used to change the base translucency so even solid textures are semi transparent when you change this to 50.

However, some of the train sim exporters use values of 0 to indicate the texture is solid and/or has totally transparent areas.

The lower values of 1,2 or 3 are also sometimes used to indicate a texture with translucency (which needs to be drawn at a a different time to the rest by the game engine (alpha sorting)