I figured this out, I think, after my initial post.
If you have the button enabled for sync selection, you can see all the UV’s and it highlights which ones you’re editing. This is the easiest way to see things.
ONLY, if you select the edge of a UV island, it selects every other UV that shares that vertex. This is Not helpful.
If you want to Not do that, you have to turn that off, and select all in the 3D view, so you can see the UV’s. First, What’s the point of doing That? I feel like only showing Some of the UV’s at one time should be an advanced option, not the default.
OK, rant over. Is there a way around this? It seems I have to keep that sync on, until I want to touch one of the UV island edges, then remember to turn it off else I change parts that I didn’t want to.
The reason the multiple uv islands gets selected when you select edges on the island boundaries is because those edges/vertices are shared on the actual model. The only way you’ll be able to select uv island boundary edges without it selecting other shared vertices while in sync selection mode, is if you separate those areas on the actual mesh.
If you only want to select a single uv island while in sync mode, just switch you selection mode to face select mode. (While in edit mode press ctrl + tab)
This is also a pragmatic reason why a model is often best composed as a collection … that is to say, a group … of individual Blender-objects. (Designate some “empty,” some distance away from the object itself, as “the handle to grab onto and move the whole thing around.”)
You state the problem like this is the only way. I just want to be clear that it is not. It may be the only way in Blender currently, but it isn’t “correct.” The reason I am in sync mode is to more easily understand the correlation between the selected UV, and the shared vertex.
I know that UV’s are interesting because one vertex May actually be 4/5 different UV points. More if your model isn’t set up for SubD surfacing. So selecting the vertex should highlight all of the UV points.
But selecting the other way around, shouldn’t mean that all of the UV points are selected.
Software treats it differently for different purposes. One I’ve used, and it’s the method I prefer, highlights the shared UV’s but in a different color. This informs you of their relationship, but you wouldn’t accidentally move it. A secondary action allows you to select the shared UVs. In most cases, selecting one or two edge UVs, you wouldn’t want to Also select the shared UVs on a different island.
In my case, this is a glove. There are 3 pieces, split by material, just because that’s how the graphics are created. The top of glove, palm/bottom, and a strip between the fingers that has no graphics and is just a flexible piece of fabric.
The model itself is smoothed. I wouldn’t want those to be split up into different objects. Doing it as one object also lightens the scene a bit if you are doing something like bringing it into a game engine. Splitting objects that Could have shared vertexes spends more video memory. Also I can create 3 materials as 1 material essentially. This is also much lighter weight in terms of budget for your scene.
If you want to end up using some advanced lighting on something like a phone, then you’ll need to save those few things anywhere you can. And this is a great area because it doesn’t cost you anything visually.
button enabled for sync selection, you can see all the UV’s and it highlights which ones you’re editing. This is the easiest way to see things.