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UVing meshes for trim sheets in Blender 2.8


I'm new to trim sheets, but have a basic idea of how they work. What I don't really know is how to UV objects for them in Blender efficiently, and I haven't really found suitable tutorials for UVing non-symmetrical objects (videos I find are for things like symmetrical pillars, circular objects, etc)

My understanding of trim sheets is that you layout an object's UVs onto a texture(s) with tileable "sections", aka the trim sheet. This way you can use the same texture for the entire object. However, currently I only know to manually select the identical faces I want to have the same UV, and align them on top of each other. This becomes slightly easier with help from "Select Similar", but it's limited in what it can do.

Tutorials have mentioned "Follow Active Quads", but it only applies to adjacent faces when I've tried it, and I can't really find good documentation on how to use it properly.

For example, I want to have these windows use the same UV. They're not adjacent to each other, so Follow Active Quads only pieces their UVs next to each other.

So, what I've been doing is re-aligning each window's UV on top of each other to get this:

This is different from what I've seen of examples of trim sheet UVs, as there is some method of "assigning" the same UV to identically sized faces such that you only need to have one of those faces on the 0-1 grid. My current method is also extremely slow and I might as well have gone the regular route of marking seams and texturing them individually.

Additionally, while this object is relatively small, there are still lots of small faces that I want to have the same UV on the trim sheet, but selecting them with "Select Similar" doesn't work that great, as it often selects extra faces that fit the parameter (i.e. area, perimeter, coplanar).

1. How do I UV for trim sheets efficiently?
2. Is there a way to select identical faces (like the windows i mentioned) quickly and more accurately than "Select Similar"?
3. The object in the pictures was not made by me, so I was wondering why the edges are all marked sharp? The only time I've used that is for when I'm using Auto-Smooth, which is not the case here. Does that have something to do with how trim sheets are used?

Thanks for the help!
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