Texture Padding
Color extended beyond UV island edges
Also known as: Edge padding · Dilation · Bleed · UV padding · Texture bleed · Edge bleed
Definition
Texture padding, also called dilation or bleed, extends an island's color a few pixels past its UV border so texture filtering and mipmaps do not pick up the empty background. Without padding you get dark or wrongly colored lines along UV edges and seams, especially at a distance. More padding is needed on higher-resolution textures and for objects seen from far away, because mipmaps shrink the texture and the padding with it.
In production
Leave a gap between UV islands when you pack them, and export from Substance Painter with dilation turned on. As a rule of thumb, a few pixels at 1K and 8 to 16 at 4K, more for assets seen from far away. The same idea fixes black edges on cutout textures: the color has to continue outside the alpha edge. Padding is an export setting, so if seams show, check it before touching the UVs.
