Ok, I tested the .blend etc and:
The current, stable, Blender Octane can't understand Vertex color etc (that's why that node is red).
So your option then is to switch the "Format" for Dynamic Paint to "Image sequence" (instead of "Vertex"), and then bake it to the image sequence and use that sequence (via an Image Texture node) in your material (instead of the left node, that's currently red).
Now, linograndiotoy is using a test version of Octane + Octane Blender (which he forgot to mention..
), you can download it from the Releases board and the latest is "2018.1 RC3 - 17.3 [TEST]". You can (if your careful) install it next to the stable release (just change the install directory for both the server and Blender), just make sure you know which server you have running atm etc.
If you do that, the node setup (from dyno.blend) that your using should work fine!
Btw, by "Texture Mode" I meant "Textured view(port) (mode)".
- TextureShadingMode.png (35.65 KiB) Viewed 4494 times