'T-vertices' is a term used in computer graphics to describe a problem that can occur during mesh refinement or mesh simplification. The most common case occurs in naive implementations of continuous level of detail, where a finer-level mesh is 'sewed' together with a courser-level mesh by simply aligning the finer-vertices on the edges of the course polygons. The result is a continuous mesh, however due to the nature of the z-buffer and certain lighting algorithms such as gouraud shading, visual artifacts are often visible.