Question on using geometryFromMesh

Hi all,

I came across a problem when using geometryFromMesh. I have a mesh file for a 3D geometry generated from COMSOL, and I would like to use it in pde toolbox in MATLAB. The COMSOL file contains the coordinates for the nodes, which is a Nnodes-by-3 matrix and the element information which is a Nelements-by-4 matrix. I rearranged the node matrix and element matrix, and put them in the form in 3-by-Nodes form and 4-by-Nelements form as indicated in https://www.mathworks.com/help/pde/ug/pde.pdemodel.geometryfrommesh.html#buvjb86-nodes

However, there is still a warning saying that there is node ID missing and it should start from 1. However, if I add a row for node ID the matrix will not be 3-by-Nodes.

Is there anything that I missed that caused this problem?

Than you very much!

Best regards,

Shengyue

Answer 1

[Ravi Kumar]

It looks like the node IDs from COMSOL might be 0 based. That is first node ID in COMSOL may be 0, in MATLAB it must be 1. You can check this by:

min(elementMatrix,[],'all')

If the answer is 0, then you need to just add 1 to elementMatrix:

elementMatrix = elementMatrix+1;

Regards,

Ravi

[Shengyue Shan]

Hi Ravi,

Thanks for your answer! It works!

Best regards,

Shengyue Shan