Boundary condition from stl

General
1

Dear community.

I’m sorry if this kind of problem has already been raised here.
I’m trying to solve a Laplace equation in a complex domain (an stl file that I cleaned up and did a lot of procedures on to get something acceptable).
I managed to mark my surfaces (4) for the boundary conditions. When I import into FEniCS, I impose Dirichlet conditions on all 4 surfaces. FEniCS can indeed read the surfaces but it seems to me that it does not assign the required value to the surface for the boundary condition. when I import the result into paraview, everything is yellow and I have no solution. however, FEniCS manages to respect the conditions on two of the 4 surfaces. to check that it was not my code that was causing the problem, I tested it on a simple geometry and it works very well.
Please, has anyone already encountered this kind of problem, your help would be invaluable.

Thank you in advance. I hope I have explained the problem correctly.

2

It’s going to be very hard for anyone to help unless you can share a simplified version of your mesh.

3

Please note that you should debug your boundary condition by simply applying it to a function, and storing it to file, seeing if the condition is added.
However, as Francesco said, without a minimal reproducible example we cannot give you any further guidance.

4

Dear @dokken and @francesco-ballarin

Thank you for your help. I’ve found the solution. The error was due to the fact that for this geometry, there was a norm in the code that returned a very small value (I don’t yet know why).
I’d like to take this opportunity to ask what could cause such a small norm.

Thanks again for your help.

5

There is unfortunately no way of giving any further guidance without the actual code.

6

Dear @dokken
sorry for my late reply. I’ve finally solved the problem.
Thank for your helps.