Discussion Forum

Select "Cut Point 3D 1" as the Dataset for your Point Evaluation 1..

Jeff

Thank you for the suggestion @JeffHiller I tried and I've some difficult to see the point; I clicked on evaluate, then I selected the point evaluation 1 from the electric field section.

Immagine 2023-10-20 144901.jpg : In your Point Evaluation 1 you have not specified what quantity you want to evaluate.

Immagine 2023-10-20 145036.jpg What you did in this screenshot does not make sense to me: you set things up to plot multislices and streamlines, neither of which can live in a point, so why select Cup Point 1 as the dataset?

Best,

Jeff

PS: If you have not worked much with datasets and would rather not learn about them at this point, you could add the point in the Geometry branch, then re-solve the model. Then that point would be available for selection in post processing.

Perfect @JeffHiller; the first method works.

I tried also the second one, and I get the error in figure. Is this due to the fact that there isn't material between the object and the point?

Your latest screenshot suggests that the point is outside the computational domain, and, if so, I don't know what you could want to evaluate there.

Hi @JeffHiller It was a mistake; I'd like to know the electric field in the point (0,0,0); I fixed the problem by adding vacuum as material so that this material reach the point (0,0,0). Only yhe other material, the spherical shell, has a space charge density.

Thank you for your help.

@JeffHiller I added the vacuum, but I got this error (I used a point in the geometry so I removed the cut point 3d):

• Feature: Stationary Solver 1 (sol1/s1) Failed to find a solution. Divergence of the linear iterations. Returned solution is not converged. "Not all parameter steps returned".

The geometry is the same showed in Immagine 2023-10-20 145036.jpg but now there is also the point in (0,0,0).

How can I fix this error?

There are several possible causes for the solver not converging. I would suggest looking for these possibilities: * Check that the problem you set up has a solution. In an elliptic problem like this one, you may have imposed no flux conditions on all boundaries while having a net source (charge). * Check that the problem you set up has a unique solution. It's possible that you underconstrained the problem by not imposing the value of the potential anywhere, leaving the solution undetermined.

Please upload your .mph file so we can take a look at how you set things up.

Jeff