Hello,
You have to use the command change to change the labels. For example
labs=[22,100];
ThTmp = change(ThTmp,refe=labs);
changes the boundary label 22 to the new value 100.
You can also remove internal edges by
ThMulti = change(ThMulti,rmInternalEdges=true);
I have put the label 100 on the bottom edges, and 200 on the top edges.
porous-periodic.edp (2.0 KB)