# Geometry Nodes Separate out Alpha Channel from Vertex Colors

I'm using the RGBA channels of the vertex colors on geometry for various effects but I can't find a way to separate out the alpha channel in geometry nodes. Is there a way to access the Alpha channel of a vertex color attribute in a Geometry node?

• Sounds like you will need to use an attribute created in the shading editor to be used by the Geometry Nodes editor. Jan 31 at 11:13
• +1 good question Jan 31 at 11:15

Unfortunately, the answer is definitely: No, this is currently not possible.

A look at the source code reveals that, although an RGBA color value could in principle be processed due to the variable type, the alpha value is simply not used:

static void sh_node_seprgb_declare(NodeDeclarationBuilder &b)
{
b.is_function_node();
}


Source

In contrast, in another part of the code (compositing), which allows the separation of a color into RGBA, the alpha value is very well processed:

static void cmp_node_seprgba_declare(NodeDeclarationBuilder &b)
{