SU18PRO 3D file saved as KMZ, open in QGIS then open and save as a "shape" file

Hi all !
Trying to help a fellow employee here to NOT duplicate our efforts. We do Shade/Shadow analysis and Noise/Sound reports on some new construction projects. Right now, I build the “new” unit(s) in SU for the shadow study and he builds the same unit(s) in his noise/sound dispersion program (SoundPlan). His program won’t directly import any current SU export file types. It WILL, however, import “shape” files typical of GIS programs. Tried to get QGIS (free version 3.1) to present even a simple geo-located box saved as a KMZ from SU with no luck. Any ideas - comments - directions etc. would be MUCH appreciated!
Thanks !