I highly recommend adding support for the texture paint in Blender render, so we can draw on the object during the octane preview rendering.
Current OC Blender build has 2 issues about texture painting
1. After clicking the [Add Texture Paint Slot] button in the Context menu using material mode, it adds a Blender built-in texture node, not the Octane image texture node
2. If I add an Octane image texture node selecting the texture created in step 1 without deleting the built-in texture node, I can successfully paint over the object in viewport shading. However, during render preview, the viewport won't refresh after we paint until we re-enter the render preview.
I believe these 2 issues just need a quick fix. Please consider adding it to the development.
The best solution I believe is to make the OC Blender accept the Blender built-in image node
Thanks