We often run into the situation where we have a texture that has the alpha built into the Alpha channel (for example PNGs)

By default the octane RGB image only loads the rgb channels of a texture.

To get the alpha of an image texture we have two options:

1. The alpha image node

   

   This node loads only the alpha into the main rgb channels, so you can connect it directly to the opacity input of your material

2. RGB image with “color4” setting + mtlxseperate4

   Since octane 2026 the RGB image node now has the option to load all 4 channels of an image so RGB+A

   

   Now to be able to use this channel in a material we need to extract the alpha channel. As of 2026.1 there is no octane native way to do this, but since Octane texture nodes are fully compatible with mtlx ones we can use the mtlx seperate 4 node, where we can get the alpha channel from the 4th output: