Contour Stretch UV mapping

Contour Stretch UV mapping lets you project a texture image onto a selection of an object's polygons. Rather than projecting according to a specific form, a contour stretch mapping analyzes a four-cornered selection to determine how best to stretch the polygons' UV coordinates over the image.

Contour stretch mappings do not have the same alignment and positioning options as other mapping methods. Instead, you select a stretching method that is appropriate to the selection's topology and complexity.

Contour stretch mappings are useful for a number of different texturing tasks, particularly for applying textures to tracks and roads on irregular, terrain-like meshes. They are also useful for fitting regular-shaped textures onto curved meshes. For example, they would be useful to place a label texture on a beer bottle, right at the junction of the bottle's neck and body.

Although the easiest geometry to contour stretch is a rectangular grid of quads, it's more likely that you'll want to use contour stretch projections on less regular shapes. For best results, ensure your selection fulfills the following requirements:

• The selection cannot be a whole object, it must be a selection of polygon faces with an identifiable contour.
• Although the selection doesn't have to be perfectly rectangular, the contour stretch projection must be able to derive four corners from its contour.
• If the selection has holes in it, it is more likely to produce undesirable results.
• If the selection consists of two or more discontiguous shells, their UV coordinates do not remain separated in the UV Editor once the projection is applied. Instead, they are treated as a single, one-piece selection.