Mesh

A mesh is the structure of vertices, edges and faces that together form the outer shell of a 3D object. If a polygon is a single brick, the mesh is the whole wall. Render engines, game engines and 3D printers all read geometry as a mesh in the end.

What makes a good mesh

Quality is not just a matter of polygon count; the way the faces are arranged, known as topology, matters too. A mesh made of regular quads behaves cleanly when it is smoothed or deformed. Surface normals, the direction each face points, must be consistent: flipped faces show up in renders as black patches or walls that seem to vanish. For 3D printing the mesh has to form a closed, watertight volume with no holes.

Meshes in an architectural workflow

NURBS and BIM models are converted to meshes when they are rendered or exported. Formats such as OBJ, FBX and STL carry geometry as meshes. Point clouds from photogrammetry and laser scanning are usually turned into meshes as well, and because those are extremely dense they need decimating before use. When downloading furniture or plant models, checking how heavy the mesh is saves you from a scene that grinds to a halt later. Our 3D modeling and rendering tips explain how to prepare a model before rendering.