Hello,

I am working on a 3D topology optimization code in Matlab. Currently, I am looking for a strategy to create passive zones. In the attached example, the red-colored part should be passive (i.e., it should not change during the optimization). I have tried several methods, but I am encountering an issue.

Here is a part of the code where I am trying to select the passive zone:

fixed = 1 : 3 * ( nely + 1 ) * ( nelz + 1 );

pa1=[];

for px=1:nelx

for pz=1:nelz

for py=((nely/2-1):(nely/2+1))

pa1= [pa1;px+((pz/2)+1)*nelx+(py-1)*nelx*nelz];

end

end

end

pasS=pa1;

pasV=[];