Stress Result in Shells
Moderator: bernd
Forum rules
and Helpful information for the FEM forum
and Helpful information for the FEM forum
Re: Stress Result in Shells
We would need such a node numbering sheme from FreeCAD (med) to vtk like we did for CalculiX FEM_Mesh_CalculiX
Re: Stress Result in Shells
yep, some volumes are not yet supported at all (penta15) and some do not work (penta6, hexa8 and hexa20) . Since we are before the release I deactivated them ATM. Thus FreeCAD should not crash anymore. It will need some further development.
https://github.com/FreeCAD/FreeCAD/pull/1362
https://github.com/FreeCAD/FreeCAD/pull/1362
Re: Stress Result in Shells
@HarryvL:bernd wrote: ↑Tue Mar 13, 2018 2:21 pm We would need such a node numbering sheme from FreeCAD (med) to vtk like we did for CalculiX FEM_Mesh_CalculiX
We need the node assignments for VTK. Best would be some table how to convert from FreeCAD to vtk. Something like this FEM_Mesh_CalculiX Do you know any resource for this.
Re: Stress Result in Shells
Shell elements expanded to C3D15 are shown correctly in paraview.
Translation .frd->.vtk done with: https://forum.freecadweb.org/viewtopic. ... &hilit=vtk
Please see source available in this thread (file: "Eksporty.cs")
Translation .frd->.vtk done with: https://forum.freecadweb.org/viewtopic. ... &hilit=vtk
Please see source available in this thread (file: "Eksporty.cs")
Code: Select all
.
.
.
// determine main nodes total number
// elements ccx no.5 (15 node wedge) as they are not supported in VTK
// has to be exported as type ccx type 2 (VTK typ 13)
// additional nodes has to be ommited
int nn = 0;
foreach (KeyValuePair<int, tNode> KVP in NodeTab)
if (KVP.Value.IsFirst)
nn++;
// total number of elements
.
.
.
Re: Stress Result in Shells
does it mean penta15 in frd = penta15 in vtk ?
BTW: I assume conversion from tetra10 in FreeCAD to vtk is wrong, thus we gone get all the black models. see hint of werner https://forum.freecadweb.org/viewtopic. ... 30#p125688
BTW: I assume conversion from tetra10 in FreeCAD to vtk is wrong, thus we gone get all the black models. see hint of werner https://forum.freecadweb.org/viewtopic. ... 30#p125688
Re: Stress Result in Shells
I think not.
mamah uses vtk file version 2.0, and there is no 2nd order wedge available, so he uses a 1st order wedge and drops additional nodes
frd elem no 5 -> vtk cell type 13
Meanwhile we are using vtk file version 4.0. I think now there is a 2nd order wedge.
Please see here:
https://www.vtk.org/doc/nightly/html/vt ... ource.html
Code: Select all
typedef enum {
// Linear cells
VTK_EMPTY_CELL = 0,
VTK_VERTEX = 1,
VTK_POLY_VERTEX = 2,
VTK_LINE = 3,
VTK_POLY_LINE = 4,
VTK_TRIANGLE = 5,
VTK_TRIANGLE_STRIP = 6,
VTK_POLYGON = 7,
VTK_PIXEL = 8,
VTK_QUAD = 9,
VTK_TETRA = 10,
VTK_VOXEL = 11,
VTK_HEXAHEDRON = 12,
VTK_WEDGE = 13,
VTK_PYRAMID = 14,
VTK_PENTAGONAL_PRISM = 15,
VTK_HEXAGONAL_PRISM = 16,
// Quadratic, isoparametric cells
VTK_QUADRATIC_EDGE = 21,
VTK_QUADRATIC_TRIANGLE = 22,
VTK_QUADRATIC_QUAD = 23,
VTK_QUADRATIC_POLYGON = 36,
VTK_QUADRATIC_TETRA = 24,
VTK_QUADRATIC_HEXAHEDRON = 25,
VTK_QUADRATIC_WEDGE = 26,
VTK_QUADRATIC_PYRAMID = 27,
VTK_BIQUADRATIC_QUAD = 28,
VTK_TRIQUADRATIC_HEXAHEDRON = 29,
VTK_QUADRATIC_LINEAR_QUAD = 30,
VTK_QUADRATIC_LINEAR_WEDGE = 31,
VTK_BIQUADRATIC_QUADRATIC_WEDGE = 32,
VTK_BIQUADRATIC_QUADRATIC_HEXAHEDRON = 33,
VTK_BIQUADRATIC_TRIANGLE = 34,
Re: Stress Result in Shells
ahh ... found this https://www.vtk.org/data-model/ and https://www.vtk.org/wp-content/uploads/ ... ormats.pdf page 9 and 10, so no quadratic wedge ...
Re: Stress Result in Shells
@Bernd, that's where I got my picture for a "VTK WEDGE (=13)" from.
@UR_, yes that's what I proposed - only export the first 6 of the 15 nodes.
@UR_, yes that's what I proposed - only export the first 6 of the 15 nodes.
Re: Stress Result in Shells
@ UR_: VTK_BIQUADRATIC_QUADRATIC_WEDGE = 32, indeed seems to indicate the required VTK cell for a 15-noded wedge is implemented, but in Schroeder's book for version 4.0 there is only mention of 14 linear cell types. Perhaps the quadratic cells are still under development?
Re: Stress Result in Shells
Check actual vtk user's guide https://www.vtk.org/vtk-users-guide/ directly https://www.kitware.com/products/books/ ... sGuide.pdf around page 481 (legacy formatting starts few pages above). There is quadratic wedge, but when I was implementing this to my optimizer I skipped quadratic wedge, probably I had an old manual. That time I didn't care about node ordering - in the same order I read nodes from inp file I print them to vtk file.bernd wrote: ↑Wed Mar 14, 2018 1:43 am ahh ... found this https://www.vtk.org/data-model/ and https://www.vtk.org/wp-content/uploads/ ... ormats.pdf page 9 and 10, so no quadratic wedge ...
I checked it quickly by comparison of https://www.freecadweb.org/wiki/FEM_Mesh_CalculiX and VTK users guid mentioned above. VTK node order is same as in CalculiX but VTK is 0 based, which makes practically no difference.
EDIT: only 1D quadratic element is an exception.