A mesh is a special collection of simple single-sided facets or parts. These parts need not have any spatial or topological relationship between each other. A mesh is referenced geometry containing a common vertex pool, vertex normal pool, and texture coordinate pool. The individual parts of the mesh represent single sided faces with planar polygon structure. The orientation of each mesh part is determined using the same rule as for faces. The parts of a mesh are defined by indices into the common pool. By allowing reuse of shared vertices, the physical representation size of a mesh can be smaller than an equivalent collection of surfaces.
In the example, P0 to P4 are represented as mesh parts, and vertices v0 to v8 are stored in a common vertex pool. The definition of a part is given by a list of vertex indices that reference the common vertex pool. For example, P2 is defined by the vertex index list containing the indices 6, 7, 4, 3, and 6.
Contained by: IFMECompositeSurface, IFMEMultiSurface