UV > Pack Islands. Can this do what i want?

hi everyone. I’m unwrapping a complex, asymmetrica, organic object that i’ve had to use a lot of seams on, and as a result the uvmap has a lot of small, irregularly shaped islands. This is fine, i can cope with it. But The unwrapping places them by default in a very inefficient arrangement, with lots of wasted space in between.

I would think from the description, that the Pack islands feature would move all the islands around to fit them more tightly into the available space, however it does not. When i select multiple islands and use the PA feature, all that it does is move and uniformly scale the entire group of islands, to fill the whole UV image. It does not move the islands relative to each other, and therefore does nothing to fix the wasted space between islands.

what i would hope/expect would be a feature that moves each individual island around to pack them as close together as possible, perhaps even scaling or rotating them to use space more efficiently. The rotation of the UV islands isn’t important to me.

is there any way for blender to do this automatically? perhaps even a plugin or add-on? it will be quite a pain to neaten this up manually, and that’s something i’d have to repeat each time i tweak the seam arrangement :frowning:

The algoritm you are looking for is not as simple as you might think, especially when you add rotation and scaling into the mix. Nor would it be very useful, as the desisions it would make automatically would be wrong more times than right.

You may want to consider fewer seams and using pinning to unwrap your object.

Is the model low-poly or still high-poly? I assume you’re unwrapping to import/create a game asset in-which case I would completely ignore Blender’s UV unwrapping tools. It’s O.K. for simple jobs but you’ll need something like Headus UVLayout to efficiently create proportional and accurate islands from bloat and reforming.

I won’t say how you can download the software as it’s obviously payed for, but I’m sure you can get it from a questionable source - so to speak…

hii x my model is very low poly (300-ish triangles), it’s just an extremely unmanageable shape because it’s part of a hairstyle, and is therefore irregular and organic. i’m on a tight poly limit and quads are not allowed.

here’s a picture:


In the topright you can see the uv layout i’ve got so far. I’m really not happy with it, although i’m not sure how it could be better. As you can see this shape really has no significant edge loops or natural seams, and the pointy things sticking out all over defy normal unwrapping methods, without compressing themselves into a tiny texture area and looking horrible.

how the heck do you unwrap a shape like this? :<

Interesting problem. Imagine that hair as a bundle of locks, running from the base to the furthest pointy tip, with shorter locks layered on top of the long locks. Looks like you have four main long locks. Find them, and separate them with seams. Then select the faces in each lock, one lock at a time, and deselect any faces from the smaller locks layered on top of the main lock. Unwrap the main lock. Only the selected faces will show up in the UV editor. Arrange those faces so they are either vertical or horizontal (to make texturing strands easier), scale them up to a decent size (use about 1/4 of the layout area), and pin them. Then go back to the model, select the overlapping layered locks you deselected before, and unwrap them. Put these (probably disconnected islands of two or three tris) next to the already unwrapped lock. Scale them up so the tris are all roughly the same size, and pin them.

Do this for each of the four main locks of hair.

Map a strand texture onto the UV layout, and check the textured mesh. You will probably find strands pointing crosswise on some of the small outer layers. Select them so they light up in the UV layout, and rotate them so the strands go in the same direction as the strands on the lock they are layered on top of.