Triangulation

Triangulation is the process of converting polygons (typically quads or n-gons) into triangles. In 3D modelling and real-time rendering this is necessary because graphics hardware and engines use triangles as the fundamental unit to render surfaces. The way polygons are triangulated affects topology, shading (vertex normals), UVs and animation: how a polygon is split can cause visible seams, pinching or unnatural deformation. Modelers may rely on automatic triangulation on export or triangulate manually to preserve edge flow and control deformation for skinned characters.

Imagine you model a character in Blender using mostly quads. Before exporting to Unity, you check the triangulation: Blender can triangulate automatically on export or you use a Triangulate modifier to preview how quads split into triangles. If a quad is non-planar, the chosen diagonal can change shading and deformation during animation, so you might manually triangulate critical edges to avoid bad skinning artifacts. Triangulation is also important when creating collision meshes or level geometry to ensure predictable behaviour and good performance in the engine.