Problem interpolating between meshes

Dear all.

I am having an issue interpolating between two meshes. I have a first mesh like the first figure provided by other code


I have defined a mesh in the same domain (in FreeFem) and interpolated the data from one mesh to the other. I found that the points near the surface of the square cylinder are not properly calculated. I have read in the documentation (page 196) that to speed-up the process the interior of the objects are also triangulated. That can be the reason of this variation?

How can I solve this problem?

Can you send the 2 meshes to see what is the problem,
and also say which is the finite element.

Dear Frederic.

Thanks for the interest. I have used P1 FEM. I send to you the meshes, the solution files and a edp file to read and perform the interpolation.

Best regards.-
InterpolationProblem.targz (912.3 KB)

I thing the problem do not come from freefem++

I have try to see the solution close the square

readMeshesInterpolate.edp (1012 Bytes)