What is the best way to unwrap a round cube for a 512x512 pixel texture size?


I added a round cube.

I created a new texture in the UV/Image editor: 512px x 512px

Then in “Edit Mode” I selected all faces from the round cube and then I did this:
UV Mapping -> Follow Active Quads

This is the result:

How can I unwrap a round cube without making unused areas?


That’s typical of UV maps, you’ll always have empty space. The only way, depending on how you intend to texture it, would be to separate each “face” (i.e. square grids) so they have more chance of filling space. However, if you are just texturingh within Blender, you could run into issues with texture orientation. If you are taking it into something like Substance Painter, it isn’t so much of an issue. The most effective use of space would be something like lightmap, but that literally splits every face.

This shows what I mean, even with each grid split, given the geometry, there’s still a lot of wasted space.

My favorite unwrap on a polysphere is like the seams on a tennis ball that form two islands. It fills ~2/3 and is a rectangle so you could scale them a little on u to fill entirely.

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@colkai How you did that? It looks better than my solution. EDIT: I understand. You marked the seams. OK. But how you unwrapped it? Maybe unwrapped with “Follow Active Quads” and then placed on different positions?

@Photox Squares are better to handle. But also a good solution.

How best to unwrap it depends on what “it” is, and what it’s relationship will be to the camera and other meshes. You can hide seams out of view and shrink or even exclude areas out of view.

And forcing the layout into a perfectly square grid is not necessarily the best idea. You’re maximizing space usage, yes, but the object and it’s polygons are not square, so you’re introducing extra stretching as the trade-off. Just keep that in mind.

No space wasted, but not square.

I used a combination of addons, Magic UV for copy/paste of UV mapping

… and UV Quad Unwrap to get the clean quads without the distortion you sometimes get with “follow active quads”.

I marked the seams for each grid face, then did unwrap, which gives you rounded faces, I then selected one face and select linked with delimit by seam, ran the UV Quad unwrap. selected those faces, copied the UV, inverted the selection, pasted the UV, then in the UV window just hit CTRL+P to pack.

To be honest, given the curvature, you really don’t want purely straight quads as the texture will distort slightly when applied, given the surface is actually curved. But htat said, it is good for adding straight lines on a curved surface.