Baking two textures into one

Question

I need to do the following - import two different Collada-files, join them into one and combine their textures to one texture. So, the output should be one Collada file with just one texture. I am trying to bake textures like here: How to combine two different textures into one but get some strange result in the baked texture. Just for example - here is the joined object with two materials (and two textures):

When i try to bake the textures I switch to the Edit mode, select everything with A, push Bake in the render menu and get the following strange baked texture:

What approach should I choose to make the correct texture and material?

I will describe the way I worked step-by-step:

1. Load the first and the second model
2. Position the models side-by-side (just like on the first screenshot)
3. Created a new UV Map
4. Created a new image in UV Image Editor with default size (1024x1024)
5. Created a new material for the baked textures
6. Went to the Texture tab with the material selected and in the material textures tab created a new texture
7. In the texture selected the image created in step 4
8. Went to the Render Tab
9. Switched to the Edit Mode, selected everything with A in 3D View.
10. In the UV Image Editor switched to the image to which I want everything to bake
11. Push the Bake button in the Render Tab

12. Got this strange result.

    What I have missed?

Thanks in advance!

Answer 1

When objects were separate, they had their own UV maps as they should have been textured. Let's assume these are called "UVmap" as by default.
Objects had their materials, I assume they were called "Material_1" and "Material_2"; let's call the new material created esspecially for the bake as "Material_Bake".

After joining objects create new UV map and call it "UVmap_For Bake". Make some arrangements on that new UV map so faces not overlap there (the easiest way is to press Ctrl + P with everything selected that you'd like to rearrange while in UV/Image Editor).

For "Material_1" and "Material_2" in Texture tab, Mapping scroll set Map option to "UVMap", so that the original images are mapped using original map.
For "Material_Bake" choose in Texture > Mapping > Map your new UV map "UVmap_For Bake" so that baked texture to be mapped on the both objects with arranged map:

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It seems in your file "BakedMaterial" was assigned to all the model's faces, therefore others didn't affect on the final result.
The original materials should be assigned to those parts of mesh which they were created for.
After joining, you create that new material, but don't assign it to anything or you'll get circular reference in texture stack, empty result, rewritten images etc. Just create it and proceed to the next steps. You can look at 2 ways of how materials were assigned below.

It's most likely that you won't get expected result of baking in the second case.

The file below is the one with the result of incorrect baking, slightly edited. Open it, press Bake and enjoy. It'll bake generated images of one color (unfortunately your files weren't packed) into "Texture_For_Baking" texture.

Answer 2

Finally, I have found the correct way for baking textures for my files. There is a great tutorial here: https://youtu.be/Tj-S5QAac3U Following all steps exactly as was shown in the video I got the correct result just in 10 minutes. Hope, this will save time to someone.