How to edit UV-mapped Images - while they're mapped to the mesh?

Which possibilities are there if you wish to edit an uv mapped image - while it’s still mapped to the mesh, so you can see what you’re doing?

I kind of hoped that images might survive .obj, so I could export an entire project to Photoshop and then edit the image, but that doesn’t seem to be the case.

Are there any other ways to do this?

I should add that I’m going to use Octane Render, so Texture Paint is not an option as I understand it.

You can edit images in Texture Paint mode. You can also save images(as png, tga, etc.) and edit them in Photoshop. Or am I not understanding your question?

EDIT: Why would texture paint not be an option because of the render engine you’re using?

I should add that I’m going to use Octane Render, so Texture Paint is not an option as I understand it.

This makes no sense, unless you mean that you can’t use images in Octane, which is wrong since you can.

Well, perhaps I’ve misunderstood what the Octane Render guys say then: “You should use only OctaneRender materials inside Blender scenes - the plugin knows nothing about Blender specific materials and textures”.

I was under the impression that Texture Paint would paint directly on the mesh; on the vertices, as opposed to actually editing the png?

But I would absolutely love to be wrong.

So you’re saying that I can draw or paint directly on the mapped png/jpeg/etc. inside Blender, in the viewport? Forgive me for repeating this, but I already gave it shot and couldn’t make it work.

EDIT: Yes, I’m aware that I can export the images - or the mesh - to Photoshop and edit them there, but I wish to edit the images while they’re still ‘glued’ to the mesh so the edit can follow the exact form of the mesh…

If you’re just painting textures, the material is mostly irrelevant. You can UV map a texture to a model and paint on it in texture mode regardless of how you plan to render it later. Texture Paint mode paints on an image file. You’re thinking of Vertex Paint mode, which paints on the mesh rather than on a texture image. Whether you’re going to ultimately use the texture in BI, Cycles, Octane, or anything else, it’s still just an image file, likely a .png file. Images are just images, no matter what render engine.

I usually leave Blender in Blender Render while I’m making textures, because it has baking capabilities that Cycles currently lacks. I do this no matter how I plan to render, because I’ll just load the resulting image later when I create the appropriate material.

Yes, Texture Paint allows you to paint on the image, either in the viewport(on the mesh) or in the UV/Image Editor.

Well, I tried Texture Paint again and got the same result as I’ve got before: Tools behave very odd: Brushes are unpredictable; jump around; the brush paints to the right when I move it to the left; it paints only what seems to be random parts of the image, and Blender freezes.

More importantly, edits only show in Texture Mode and in the UV Editor. They don’t render at all.

So I really don’t understand what you’re saying; that Texture Paint paints on an image file. But I’ll try again tomorrow…

Thank you. Please see my reply to K Horseman. I’ve tried Texture Paint a couple of times now and get the same result each time: Brushes behave strange; edits are only visible in the UV-Editor and in Texture mode, and don’t appear at all in Octane’s render.

The octane integrated plugin does not recognize blender texture datablocks, the octane engine loads files from the disk independently of blender. You will have to switch to blender internal if you want to paint in the 3d view and then save texture changes back to the texture file, then switch back to octane. The octane fourms warn of issues having blender and octane materials in the same file so proceed with caution and save often. You might use a separate blend for texture painting.

Texture painting should work pretty much just like painting on a physical model. If you’re getting odd results in texture paint mode, there’s something wrong with your mesh object. It may have unapplied scaling or rotation, or you might be using the UV map incorrectly in some way. You should post a .blend file that demonstrates this brush-jumping behavior so we can diagnose the problem.

As for it not rendering, you need to create a material. All you’re doing in texture paint is creating an image texture that lines up with the UV coordinates of the mesh. Your material will have options for applying textures within it. Octane uses its own material system, as does Blender Internal, Cycles, and anything else. You’ll have to create an Octane material when the time comes, but image textures are just images no matter what the render engine. As I suggested earlier and justavisitor confirmed, you should be in Blender Internal when you’re creating textures, but once those images are all ready, you’ll do the rest in Octane.

jandress and K Horseman,
Thank you both! This (do the work in Blender internal) really makes sense.

After what I’ve seen so far, though, I think the warnings against mixing Blender and Octane materials should be taken pretty seriously, so yes, I’ll do the work in one or more copies of the project and copy the resulting image file back into the original project.

Again, thank you both, now I know in which direction to proceed.

Hello again,
I tried shifting between Blender internal and Octane as discussed, but the png maps differently in the two setups, which means there’ll be additional adjustment to do when images are moved between the setups.

I’ll try the Autorefresh software instead.