[MOAB-dev] Quadratic pyramid faces

[Jacob Hochhalter]

Hello,

I'm working with moab 4.7, compiled during a petsc install, and have 
noticed some strange behavior with quadratic pyramids.  I'll do my best 
to explain below, without writing too much - let me know if more detail 
is needed.

Upon making a set of face entities, consisting of the quadrilateral 
faces on a pyramid, moab generates "Tri7" and "Quad7" faces.  The Tri7 
faces consist of 3 corner nodes from a triangular face and the 4 midside 
nodes from the quadrilateral face.  The Quad7 faces consist of the 4 
corner nodes from the quadrilateral face and 3 midisde nodes from a 
triangular face.  Note, linear pyramids work fine.  I figured that meant 
that there was some inconsistency in the face ordering and midside node 
ordering (for quadratic pyramids) and landed in MBCNArrays.hpp, after 
snooping around a bit.  There I noticed that the face indexing does not 
match the documentation that I have been referring to 
(http://homepages.cae.wisc.edu/~tautges/papers/cnmev3.pdf).  Upon making 
the change below, and rebuilding, the issue disappeared and moab 
generates "Tri6" and "Quad8" faces, as expected.

The following code from lines 89-92:
"
      // pyramid-face
    { 3, 5, {4,3,3,3,3}, {MBQUAD,MBTRI,MBTRI,MBTRI,MBTRI, MBMAXTYPE,
                          MBMAXTYPE, MBMAXTYPE, MBMAXTYPE, MBMAXTYPE, 
MBMAXTYPE, MBMAXTYPE},
      {{0,3,2,1}, {0,1,4},  {1,2,4}, {2,3,4}, {3,0,4} } },
"

should be this (the 4th face should be the quadrilateral)
"
      // pyramid-face
    { 3, 5, {3,3,3,3,4}, {MBTRI,MBTRI,MBTRI,MBTRI,MBQUAD, MBMAXTYPE,
                          MBMAXTYPE, MBMAXTYPE, MBMAXTYPE, MBMAXTYPE, 
MBMAXTYPE, MBMAXTYPE},
      { {0,1,4},  {1,2,4}, {2,3,4}, {3,0,4}, {0,3,2,1} } },
"

Thanks,
- Jake