====== Topology ======

Edge flow is affected by the **poles** contained in a model. A **pole** is any vertex that has a number of connecting edges different than 4.

When using **Subdivision modifier** this becomes very apparent and breaks the edge flow.

{{:3d:modeling:broken-edge-flow.png?direct&400|}}

On edges, bevels and crease can be used to create support topology. 

**Bevel** adds smoother topology at the expense of more vertices. 

**Crease** imitates the presence of supporting loops without adding topology but can create uneven topology if the adjacent edges are not at equal distance from creased edge.

{{:3d:modeling:edge-crease-bevel.png?direct&400}}



==== Topology Flow ====

When bridging between two meshes that have different numbers of edges / vertices, to conserve the quad based mesh and avoid n-gons use the knife tool **''K''** in a similar fashion:

{{:3d:modeling:topology-flow-1.png?direct&400|}}

This also redirects the topology flow in a sort of 180° U-turn.

The second smaller zone is made by insetting the two faces with **''B''** for boundaries activated.

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=== Going from 3 to 1 ===

{{:3d:modeling:topology-flow-2.png?direct&400|}}

This construction can bring 3 edges to a zone with one edge. Slide the middle edge inward, select the three edges and **''F''** to fill then the 1:1 edges and **''F''** to fill.

Notice the 180° turn on the edge flow again.

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=== Connecting 3 planes ===

{{:3d:modeling:topology-flow-3.png?direct&400|}}

Keeping quads in the mesh enables a better control over the shape afterwards.

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