Edge

An edge in 3D modeling is the line connection between two vertices in a mesh. Edges, together with vertices and faces, make up the model's topology and influence surface flow, subdivision behavior, and how deformations behave during animation. From a design perspective, edge flow (edge loops), hard versus soft edges, creasing, and proper edge placement are essential for predictable shading, clean UV seams, and avoiding non-manifold issues that can break rendering, texturing or 3D printing.

When modeling a face, edge loops around the eyes and mouth are used so the skin deforms naturally during animation; those loops are made of contiguous edges connecting vertices. In product design you often bevel an edge slightly so highlights look better and sharp corners don’t cause rendering artifacts. When prepping a mesh for 3D printing you also check for boundary edges or non-manifold edges: a stray edge or an edge shared by more than two faces can make the model unprintable.