On Tue, 16 Feb 2010, Rahul Sampath wrote: > HEX8: 7 6 > o--------o > /: /| > / : / | > 4 / : 5 / | > o--------o | > | o....|...o 2 > | .3 | / > | . | / > |. |/ > o--------o > 0 1 > > TET4: > 3 > o > /|\ > / | \ > / | \ > 0 o...|...o 2 > \ | / > \ | / > \|/ > o > 1 > > However, you have not shown the coordinate axes. I need to know the following: > 1) The relationship between the local coordinate system and the local > node numbering scheme. For example, In Hex8 whether the edge 0-1 is > parallel to the local xi or eta axes. > > 2) The relationship between the physical global coordinate system and > the local coordinate system. > > I believe you must already be using some convention for both to be > able to compute the Jacobian of the transformation. It would be very > helpful if you could tell me where I can find this information.
To the best of my recollection: For triangles and tets, the nodes are at (0,0,0), (1,0,0), (0,1,0), (0,0,1) in master coordinates For tensor product elements, the geometry is [-1,1]^d and the edges are 0-1:xi, 0-3:eta, 0-4:zeta For pyramids, the peak is at (0,0,1) and the base is the same as a quad. Prisms are the tensor product of a triangle and an edge, with the triangle at zeta=-1 given the lower local node numbers. I'm afraid that the only place where you can find this information solidly may be implicitly in the fe_lagrange*.C code, though; I'm not sure we've got it cleanly documented. If you'd like to add such documentation, a patch (in ASCII so we can put it in the headers) would be appreciated. --- Roy ------------------------------------------------------------------------------ SOLARIS 10 is the OS for Data Centers - provides features such as DTrace, Predictive Self Healing and Award Winning ZFS. Get Solaris 10 NOW http://p.sf.net/sfu/solaris-dev2dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
