I am new to this kind of UV unwrapping and it seems a bit strange and confusing for some reason. Wouldn't it be easier to just unwrap the objects separately and then combine them? It's pretty hard to select what I want when I have a big block of a model in edit mode.
After working on this, I finally finished it (I think). It looks ok while still in StartManualUnwrap but as soon as I finish it it looks off in certain parts of the model. Why?
Hey Fenes, the model is looking good so far!
If you find it easier to unwrap everything separately and combine later, that can work just as well 👍
My only guess for why it would look different after finishing the unwrap is if you accidentally changed the number of vertices while unwrapping (edge sliding and removing doubles, etc...). Beyond that, unfortunately, I don't know. Thankfully Blender 2.8 will allow multi-UV editing by default, so this should be much easier in the future.
Ooooh...I might have made a couple of small changes. How do I fix it?
Would you mind taking a look at the file?
https://drive.google.com/open?id=17GhMnF22Bhp57RZWn4HDJT1CHQRVrs8p
Gosh, that is pretty messed up. It looks like it swapped faces somewhat randomly, which would only happen if there's a change in vertex order. There's really only two things I can see to do unfortunately - either start the unwrap over, or separate the pieces back out and re-apply any modifiers and whatnot. Sorry there's no quick solution, but it looks like you're doing great and on the right track!