Additional property option to the unwrap operator. Sample the bounding box of the current selected components (face,edges, verts), unwrap the selection and then position the selection within the same bounding box again. Use the same orientation by storing the position of 3 arbitrary(?) uv points of the selection before unwrapping and then orient the newly unwrapped uv’s to the roughly same orientation.
- Green outline = bounding box
- Blue outline = uniform bounding box
The goal is to unwrap only the selected uv island and keep it in the uniform bounding box.
The unwrapped uv island is scaled to fit into the uv 0-1 space (aka UDIM 1001)
The uv island is unwrapped and fitted into the original uniform bounding box. Note that this might result in overlap in some cases where uv islands are packed tight, but that is expected