I want to use a separate texture (grayscale) on a material in the Blender game engine as alpha channel of that material, because I reuse the other (rgb) texture on another, opaque material.

I set up everything as depicted in the screenshots. The preview of the material looks as expected, but in the 3D view or in game mode (p), the material is opaque.

Material setup Texture setup

How do I setup this correctly to actually see the alpha effect? Here is the test scene: http://www.file-upload.net/download-11505718/AlphaTestScene.blend.html

Edit: When I bake the alpha channel into the rgb-texture and check color and alpha in the influence, then it works. But it would be nice to have separate textures for each purpose (like specularity or bump maps).


1 Answer 1


I have pretty much the same as you have.


enter image description here

Alpha = texture that feeds alpha channel Color = texture that feeds color channel

  • Alpha color is not visible at all.
  • Where Alpha is transparent, nothing is visible
  • Where Color is transparent you see the material color
  • Where Color is opaque you see Color texture (rgb)


enter image description here


enter image description here enter image description here

  • $\begingroup$ Yeah, because it seems you painted in the alpha channel of your alpha texture ;-) This is easy, however I tried to use the grayscale information of a texture to make an alpha channel. Like grayscale can be bump or specular... I guess Blender can't do it right now... Just curious why the material preview is perfect. $\endgroup$
    – Azial
    Apr 22, 2016 at 19:14
  • $\begingroup$ Ah, good point. $\endgroup$
    – Monster
    Apr 25, 2016 at 6:32
  • $\begingroup$ To use the greyscale information, try checking the "RGB to intensity" button. $\endgroup$
    – sdfgeoff
    Nov 19, 2016 at 3:57

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