Hi Folks,
I’ve got some questions regarding the pyramidal elements in vtk:
-
First of all: Why is the GetParametricCenter() different in both cells, although they span the same domain:
linear Pyra:
pcoords[0] = pcoords[1] = 0.4;
pcoords[2] = 0.2;quadr. Pyra:
pcoords[0] = pcoords[1] = 6.0/13.0; // approx 0.46
pcoords[2] = 3.0/13.0; // approx 0.23
Wouldn’t I expect that both cells have the same parametric center?
-
Regarding the EvaluatePosition() method:
If I look at how the initial position is chosenlinear Pyra:
// set initial position for Newton’s method
double params[3] = {0.3333333, 0.3333333, 0.3333333};
pcoords[0] = pcoords[1] = pcoords[2] = params[0];quadr. Pyra:
// set initial position for Newton’s method
pcoords[0] = pcoords[1] = pcoords[2] = 0.5;
double params[3] = {0.5, 0.5, 0.5};
I wonder even more:
- Why is the linear initial position set to 1./3. instead of the parametric center?
- Why is the quadratic initial position set to 0.5 instead of the parametric center? Here I wonder even more because it looks like this point is located on the surface instead of the interior, correct?
Thanks for the help.