Painting only alpha channel but showing it as visible color

Hi all :))

I’d like to know wether there’s a way ( or an addon ) that allows painting customization ?

I need to paint an alpha channel ( or a single channel texture ) with integer values ( this is for splatmapping purposes ).

And i’d like for easing the visual to show those painted pixels with various different colors.

It’s a quite specific demand, and am looking at simple painters addons in wich i could change the python code for answering my specific need…

there it is. Any idea is very welcome :))

Happy blending !

  • 3D View > Toolshelf in texture paint mode > Tools > Blend Mode = Add
  • Enable the Paint Palette addon
  • Set three colors in the Color Palette panel:
    – (1, 0, 0), (0, 1, 0), (0, 0, 1)
  • Now, you can paint on a single channel (R, G or B)

About the alpha channel:
Blender can only use the alpha channel for transparency because it multiplies RGB channels with the alpha channel (it does this with every image format). By doing this it ruins the texture, if the alpha channel stores any information other than transparency. So, if you want to author a texture in Blender whose alpha channel means sg other than transparency of the RGB channels, you have to create the alpha channel as a separate image and combine the textures in an image editor like Gimp or Photoshop. And again, this new texture won’t be usable in Blender, just in other 3d software.

.blend file (2.79):
single_channel_painting.blend (849.1 KB)

thanks a lot @helluvamesh for the blend :))

and for the advice !!

Finally i use 4 bits in the red channel of an image for splatting 16 textures.
I regret that blender don’t have textures layers, just like unity3D does. Therefore i have to use a texture atlas with all the problems from filtering. but as blender is not the final app, it not that bad.

My only lasting problem is that i write on the red channel values in the range [0;15] and i just don’t see
the visual result.
I wish i had a lil plugin ( or be able to write one ) for adding 2 buttons, light and contrast in the image editor panel :confused:
mebe there’s already one such addon ? i have to search :slight_smile:

happy blending !