Image not visible in uv editor

[bnewton81]

Can anyone tell me what I'm doing wrong? Sometimes I unwrap a mesh and open the uv editor to map it, and the texture I have selected will not open up in the uv editor. When I render, it appears it is mapping but the image won't show up in the editor. Is this a blender bug? I remember having this issue in 2.49 as well and i would just keep messing with it and then it would allow me to bring up the image in the uv editor, but I never knew if it was something I had done or a problem with blender. I currently using 2.58. It will usually happen if I texture and object and then delete that object and then try to use the same texture image on another object.

[Jojon]

This happens to me now and again. I am assuming it is a bug, but have not really tried to look far a pattern.

Anyway, I usually get around that by doing an Undo and then Redoing it, right away. ( I.e. ctrl+z directly followed by shift+ctrl+z )

[tachzusamm]

Here's the explanation:

Images in the UV-editor always "belong to faces" in the mesh (rather than to the material in the material/texture buttons).
Plus, they belong to faces which were selected (in Edit-mode) during creation or load time of the image.

Let's assume this situation:
1. We have a mesh, consisting of a plane. Let's divide this plane into two faces, A and B.
2. In Edit mode, select only face A, and load an Image_A.png in the UV editor.
3. Deselect face A, select only face B of the plane, load an Image_B.png.
4. Now deselect face B, select face A again, and Image_A.png shows up again.

Surprised? Well, this time it's (truely) a feature of Blender and not a bug. This way you *can* have different images assigned to faces, although it may sound strange, but it has it's uses.

So, if you're working with a mesh and have already an image assigned (for example a lightmap), and now you extend the mesh, for example deleting some faces and inserting new ones, those new faces DO NOT have the "previous" image assigned.

Best way to handle this behaviour: When you've modified a mesh (or haven't selected each face during image load time), enter Edit mode, select all faces - or at least each one you want the image to be assigned to - and load the image again. (Reload is NOT enough, you have to really open the file.)
And this is essential for lightmap baking for example, otherwise the lightmap will not be calculated completely.

If you load an image without having any face selected (and not in Edit mode), the UV-editor can be used of course as a pure image editor (load, new, paint, etc.), but the image will be lost (inaccessible) as soon as you select a face if you haven't saved the image file.

Hope this helps.

[bnewton81]

That help me a lot! I often do what you said and that is probably causing the issue. I wish there were a way to reset the cache or something. Some times though, it happens on my first attempt to uv map, and this single buggy thing made it take over 2 years for me to learn uv mapping. I kept running into this problem and gave up trying to figure it out. I hope I will now be able to avoid this issue.