### Topology Tutorial

Triangular Topology

Description
In these tutorials we will introduce the different topologies that exist in SOFA. Indeed, depending on the number of dimension representing our mechanical object (1D,2D or 3D), a suitable topologies has to be found.
For a linear object (1D), beams must be used. For a surface object (2D), the user can choose between different element types such as triangles or quads. And finally, for a volume object (3D), tetrahedral or hexahedral topologies are available. The choice of the element type is very important and has to be done depending on the geometry to mesh and on the aimed simulation.
Once the type of element has been properly chosen, you need to import the topology of your objects in SOFA.
- If you are using an imported mesh, you just need to use the suitable meshLoader or use the MeshTopology to load the whole object topology.
- Otherwise, you will have to define the following components in your scene file:

- SetTopologyContainer,
- SetTopologyModifier,
- SetTopologyAlgorithms,
- SetGeometryAlgorithms.

Almost all the topologies implemented in SOFA are linear elements. The implementation of quadratic elements is however possible, but the topology is to be reconsidered.

Finally, we also introduce in this tutorial the notion of TopologicalMapping. It corresponds to transformation mapping of one topology to another. It is thereby possible to get a tetrahedral mesh based on a hexahedral mesh.