Cannot create solid after importing OBJ file

Hi all, I have created an OBJ file from MATLAB containing a Schwarz Diamond unit cell. I imported it to SW using ScanTo3D, ran Mesh Prep Wizard and Surface Wizard (Automatic creation - removed surface errors). The final result is as attached.

My question now is, what next? I tried to thicken into solid, but wouldn't work. I would like to solidify the unit cell so that all the struts are fully solid. A side question, the mesh only shows when I select it, but otherwise it disappears. How do I make it display permanently?

Any help would be highly appreciated!

Thanks,

Choo

SolidworksImport export