UVunfolding

UV unfolding, also known as UV unwrapping, is a process in 3D computer graphics that maps the surface of a three-dimensional model to a two-dimensional texture space. The resulting coordinates, labeled U and V, determine how a texture image is applied to the model. The goal is to create a distortion-minimized, non-overlapping 2D layout called a UV map or texture atlas that accurately represents the model’s surface for texture sampling.

The process typically involves creating seams in the mesh to cut it into flattenable pieces, unfolding or parameterizing those pieces onto a plane, and packing the resulting UV islands within a unit square or other texture space. Once laid out, texture coordinates are assigned to the model’s vertices so that a texture image can be correctly sampled during rendering. The layout should balance coverage, packing efficiency, and the minimization of stretching.

Techniques for UV unfolding range from manual seam marking to automated methods. Parameterization approaches include conformal mapping, least squares conformal mapping, angle-based flattening, and as-rigid-as-possible (ARAP) methods. Many workflows combine automatic parameterization with manual adjustments, seam editing, and manual island repositioning to achieve better texture fidelity. Tools often support texel density balancing and padding between islands to prevent texture bleeding.

Applications of UV unfolding are widespread in game production, animated films, and 3D asset pipelines. It enables texture mapping, normal and specular map baking, and the creation of texture atlases used across multiple model parts. Challenges include minimizing distortion, managing complex topologies, avoiding overlaps, and reducing visible seams.