Mio3 UV is a free Blender add-on that adds a set of UV editing tools aimed squarely at character work — straightening, aligning, gridifying and rectifying UV islands that Blender's built-in editor makes unnecessarily fiddly.
It ships with both English and Japanese interfaces, which is a small courtesy most add-ons skip and one reason it travelled well outside its original audience.
What It Actually Adds
Blender's UV editor can do most of this already, in the sense that you can technically get there with enough manual work. Mio3 UV turns multi-step operations into single ones:
- Straighten — force a curved strip of UVs into a straight line, the fix for sleeves, straps and belts
- Gridify / Rectify — square up an island into an even grid, which makes texel density predictable and texturing far easier
- Align and distribute — tidy islands relative to each other rather than nudging each by hand
- Projection unwrap — quick unwraps from a view or axis
- Symmetrise — mirror UVs to match a symmetrical mesh, essential on characters
Why Character Artists Care
Character UVs have a specific problem: long tubular forms. Arms, legs, fingers, straps and hair strips all unwrap into curved, uneven ribbons that waste UV space and make texture painting awkward.
Straightening and gridifying those islands turns them into clean rectangles. That packs tighter, gives consistent texel density, and means a stripe painted in Substance actually runs straight along the limb instead of wobbling.
Installing It
Available through Blender Extensions, so it installs from inside Blender — Edit, Preferences, Get Extensions, search for it. No zip file handling required.
Mio3 UV vs UniV
Both are free UV toolkits and there is real overlap. UniV is broader — a large general set of UV operators including packing and stitching. Mio3 UV is narrower and more opinionated, with its strongest tools aimed at character-shaped problems.
They install side by side without conflict, and plenty of people run both.
Worth Knowing
This is a quality-of-life add-on, not a replacement for understanding UVs. It will not decide where your seams go, and a badly seamed model produces bad UVs no matter which tool straightens them.
More free UV tools in our UV unwrapping add-ons roundup.
Creator: mio3io · Price: Free · Get it: Blender Extensions