Parts of the same object appearing in different parts of the UV map

First off, I know I’ve been pretty active here over the past few days and that I’ve been creating quite a few topics asking questions. It just seems like every time I manage to solve one problem, I wind up creating several more which I can’t seem to find answers for. So I want to apologize if I’ve become an annoyance to some.

Anyway, I’ve noticed that when creating a UV map, the unwrapped image for a single part of the model will appear, or be divided, across multiple parts of the map, like so.

I believe this will cause issues with texturing, as this issue makes it impossible to apply a texture to the map and have it appear only on the right areas. Furthermore, selecting the entire object will also select all the parts on the UV map, making it difficult to move only those parts around on the map, additionally, though not always, sometimes selecting one part of the map will also select other parts which seemingly have no connection to it, (they probably do, I just don’t know how.)

If you want to move stuff in the UV editor then switch to Face mode (with UV Sync Selection turned on) or Face or Island mode (with UV Sync Selection turned off).

Imagine a cube UV unwrapped where every edge has a seam. You will have 6 identical UV islands. A single vertex in the 3D editor will be part of three separate UV islands, simply because it’s attached to, and makes up part of, three separate faces.

It seems that you’re UV unwrapping wrong in general. Selecting every edge as a seam and unwrapping is not how UV unwrapping works. The best way I’ve heard it explained - and it really does help it click - is to imagine you’re cutting your 3D model up with a pair of scissors, in a way which would make it lye flat.

Now, you wouldn’t cut a tube into 600 little squares, right? You’d cut the top and bottom circles off, and then one snip from top to bottom, and you’re then left with three flat shapes which represent the original 3D form.

Understanding that, at a basic level, will stop you having issues like this. If you want to do any kind of texturing, its essential.

I followed a tutorial by Josh Gambrell, saying that a common technique is select all sharp-edges, make some edits, and then mark them as seams…For me, it’s created mixed results.

The problem is for me, that I’ve so far had difficultly in figuring out exactly where to place seams on more complex models, I’ve known about the basic cylinder technique for a while now, but I still don’t understand going beyond that, and other simple meshes.

Thanks, but what I was meaning to say, is that parts of the same area of the model are, upon creation, all scattered across different parts of the UV map. I’m not sure if this is natural, or if there’s something that can be done to prevent this.

It depends what type of texturing your are planning to do. If you are planning to use an image, for example a tileable one, across the whole of your model then it would make sense for parts on the model next to each other to have their UV islands close to each other and aligned in the UV layout.

However, if you are UV unwrapping for other texturing methods, such as texture painting or exporting to other applications like Substance Painter, then it makes more sense to concentrate on having an efficient UV layout maximising the available space.

There are addons which will help in either case. For example I use UV Packmaster Pro a lot. It allowed me to get everything efficiently packed into a UV layout for this

Note that the UV islands for the wooden grips aren’t all sitting next to each other.

Again, thanks for the information.

Looking back on it, one the models I was experiencing issues with, (not the one pictured) was one of my earliest attempts at making a more complex model (it was a pair of headphones.) Upon further examination, I realized there were multiple accidental overlapping parts of the model created by accident. Furthermore, upon actually applying a texture, I noticed there wasn’t any real distortion or visible seams or issues despite the fact that parts of some areas were all over the place.

What I believe may have been happening was that I was just seeing those obscured copies in the UV map, and mistaking them for parts of the visible mode.

Admittedly, this entire topic on my end has been very poorly worded.

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It’s only through practice that you’ll get better at knowing where to place seams. Making sure you check for common mistakes like double vertices (select all and M>Merge by distance) or flipped normals (select all and Shift+N) before doing a U>Unwrap can help.

As for the tutorial you mentioned which talked about selecting all sharp edges and marking them as seams… I’d avoid that approach. Far better to place them yourself until you are comfortable with the whole process.

Using a temporary UV chequerboard texture can be a great way of learning to UV unwrap. It’s great for drawing attention to areas that need looked at, or where you have missed putting in seams