Quad
Four-sided polygon
Definition
A quad is a polygon with exactly four vertices, the preferred building block for clean 3D topology. Quads subdivide predictably, deform cleanly under skinning, and let edge loops flow naturally around a form. Although game engines render triangles, the source mesh is built in quads and only triangulated at export.
In production
Maya, Blender, and 3ds Max all default to quad-based modeling tools — Blender's Poly Build, Maya's Quad Draw — because a quad's four edges give a predictable, symmetric diagonal for the triangulation the engine performs on import, whereas an n-gon can triangulate ambiguously and produce different results in different DCCs or engines. This ambiguity is why a bug appears when an FBX exported from Blender shows different shading than the same mesh in Maya: the two applications chose a different diagonal split for an n-gon, producing different normals. ZBrush sculpting tools like DynaMesh generate mostly quad topology automatically, while ZRemesher explicitly targets an all-quad result because retopology and subdivision surface modeling (Catmull-Clark, used for turntable renders and some cinematic assets) both require quads to subdivide predictably without pinching at poles.
