Looking for a document that discusses surface data for structured grids in detail. Any help would be appreciated.

In particular, interested in visualizing surface data on the FACES of structured grid data (e.g. VTK-Hexahedron) - heat flux for example face-attributed (centered) data on vertex grid.

Using a Rubik’s cube example, the geometry is a structured 4x4 grid in each of the 3 dimensions (i,j,k:x,y,z). There is a desire to specify and plot data on a subset of the faces of the resultant control volumes. For any control volume, there will be 6 faces. How is the surface data and surface location specified?

The VTK User guide indicates the numbering of the vertices: 0-7, with one plane of vertices 0-3 and the other of 4-7 (from VTK User Guide, Figure 19-20). They form 6 faces: vertices 0123, 4567,1265, 0374, 0154, and 3267.