Topology

Topology is the layout of a model, how the vertices and edges are placed to create the mesh surface.

Good topology is essential if you want fast framerates (realtime) and good deformation (both realtime and pre-rendered).

For realtime rendering, bad topology can create rendering problems, see GameRenderingTerminology.

Topology Examples

• Shoulder Topology
• Limb Topology
• Face Topology
• Sphere Topology

Principles of Topology

There are no real secrets for mastering topology. Just like any other discipline, learning about good topology usually requires making the mistakes yourself in order to experience first-hand what the results are, so you understand how important it is to avoid them next time. Most people learn by doing. Reading and research is very important, but after all the reading, make sure you attempt to do it. Nothing beats hands-on learning, and repetition.

For more topology advice see SubdivisionSurfaceModeling#Primers .

Deformation

Vertices and edges need to be in certain places to give good bending/compressing/stretching when the model is skinned or morphed. Topology is the most important where the model has to deform the most: crotch/hips/butt, shoulders/armpits, mouth corners/cheeks, knees, elbows, hands/fingers.

Manifold Surfaces

Avoid T-vertices, doubled faces, gaps, flipped faces, internal unseen faces, floating vertices, etc. See

Poles

Poles can create dimples or bumps in a subdivided surface, they should be placed in flatter areas to hide them, and are best kept away from areas that deform.

Polygon Density

Add more polygons where there's curvature, less where it's straight, but balance this by the needs of the other priniciples.

Silhouette

Polygons define the shape of the model, don't waste polys where they don't add to the silhouette, depending on the requirements of the other priniciples.

Vertex Splits

See GameRenderingTerminology#Vertex_Splits

Vertex Normals

See VertexNormal