Hi Hikmat,
I have previously used cleaver to generate a volumetric mesh. There is previous discussion on discourse about this, here is the relevant text:
“I tried using cleaver with limited success. I had a lot of trouble with the extension initially. After I spoke with Andras Lasso I was able to get the meshing working. The main thing I did to get cleaver to work with my data was to create a label map with a value of 75 on the inside and -75 on the outside. I used simple filters to do the shifting and scaling.”
Here is a link to the discussion: https://discourse.slicer.org/t/usage-of-volumetric-meshes/620/3
Best,
Michael