I had to perform a reinstall of Ubuntu so I could do a clean install using APT derek@Derek-R540:~$ sudo apt install sweethome3d

WRONG!!
The instruction from download page DON'T suggest such actions.
To solve Your problem You MUST FORGET REPOSITORY VERSION!
So:
1. sudo apt purge sweethome3d (to clean repository installation);
2. Follow STRICTLY the instructions from Download page:
-download->extract->run the SweetHome3D.sh file.
Simple as this!
It work on every linux and with every SH3D version from 3.0 ~ now.
If You steel need help we are here to help you [>:D<]