Hello,
I learned that the storing of polyhedron data is in the implementation phase. Maybe I am in time to suggest an additional space reducing format for polyhedra.
In our code we are storing the polyhedron topology information in two CSR array combinations.
The first array contains the offsets and the vertices of the faces, the second array stores the offsets and the reference to the faces in the first array.
In a simple example with two hexahedra it looks like this
6 --- 5 --- 11
/ | / /|
/ | / / |
7 --- 4 --- 10 |
| /2 | 1 | / 9
| / | | /
|/ | |/
3 --- 0 --- 8
The face connectivity would look like the
0 3 2 1 #Face 0
0 1 5 4 #Face 1
1 2 6 5 #Face 2
2 3 7 6 #Face 3
0 4 7 3 #Face 5
4 5 6 7 # Face 6
8 0 1 9 #Face 7
8 9 11 10 #Face 8
9 1 5 11 #Face 9
0 8 10 4 # Face 10
10 11 5 4 #Face 11
The offsets would be
0,4,8,12 …
The faces of the polyhedra would be
0 1 2 3 4 5 6 # Hexahedron 1
7 8 9 -1 10 11 # Hexadron 2
The offsets would be
0 6 12
A negative face index indicate a face in negative orientation. The advantage is that connecting faces are stored only once.
Is it possible to consider this type of storage (or something similar) in VTKHDF?
Thanks for your great work!
Dieke