PHIGURE C REFERENCE MANUAL - DESCRIPTION OF A NON-STRUCTURED MESH OF TETRAHEDRONS

DESCRIPTION OF A NON-STRUCTURED MESH OF TETRAHEDRONS

This mesh is defined by a set of tetrahedrons. Each tetrahedron is defined by 4 vertex numbers given in an array.

The mesh must be "rebuilt" : tetrahedrons faces must be referenced exactly twice in the mesh, this means a face must belong to two mesh elements. (this is a topological and not geometric reference). Tetrahedrons face which belong to only one mesh element define the border of the mesh (or the skin of the mesh)

Tetrahedrons must be numbered as follows:

Following rule is applied: for each tetrahedron, the first 3 indices define a mesh face, and direct this face to the exterior side of the tetrahedron

Data structure for this mesh is defined by ns_tetrahedrons, Tmesh3D, Tscalar3D_data and Tvec3D_data :

num_tetrahedrons Number of tetrahedrons of the mesh
num_nodes Number of mesh nodes
tetrahedron_nodes tetrahedron_nodes[i][j] is the jth vertex of the ith tetrahedron
[forall]i 0<=i<num_tetrahedrons, [forall]j 0<=j<4
nodes array of mesh nodes
s s[i] is scalar value for ith node
v v[i] is vector value for ith node

Remark : The array nodes may include vertices which do not belong to any tetrahedron of the mesh. In this case the mesh does not provide a continuous numeration of the vertices and num_nodes is not the total number of vertices of the mesh but the dimension of nodes array.