Stretched Textures
Smeared or elongated texture detail
Also known as: Texture stretching · Stretched UVs · Texture looks smeared · Non-uniform scale texture
Quick answer
A texture looks stretched when the UVs on that part of the model are larger or smaller than the surface they cover, or when the mesh is scaled non-uniformly after UV mapping. The fix is to give the UVs an even texel density, check them against a checker pattern and remove non-uniform scale. For rocks, cliffs and terrain, world-aligned or triplanar texturing avoids stretching without perfect UVs.
How to fix it
Apply a checker texture and look for squares that turn into rectangles, then fix the UVs or the scale until they stay square and similar in size across the model. Apply scale before exporting so the mesh has a scale of 1, 1, 1. For organic surfaces that are hard to unwrap, a world-aligned material in Unreal gives consistent detail at any rotation, but check it on steep faces, where a planar projection itself can stretch.
Tools that use Stretched Textures
See also
Texel Density
Texture-to-surface ratio
UV Mapping
Unwrapping 3D meshes to 2D
Triplanar Mapping
UV-free projection from three axes
UV Seam
Where a UV island is cut
Anti-Tiling
Hide repetition in tileable textures
Apply Scale in Blender
Fix stretched bevels and uneven modifier results
UVs Not Showing in Blender
The UV Editor is empty