Here is my 3D cylinder body:



I’m doing 3D mixing in a stirring tank, with a main zone of water (A) and a small cubic section of calcium (B) being mixed (picture is a cross-section of the model). The grey section is a "mixing zone" which rotates about the "blank" zone which signifies the stirrer bar. This simulates the rotation of a stirrer bar in the liquid.



In DesignModeler, I drew the water cylinder, then drew the calcium cuboid inside that cylinder and used the Boolean command to Subtract the calcium from the water (while retaining the calcium section)


Some Interfaces have autocreated (hydrogel is just water):