If you see objects in 2D but not in 3D, then it is most likely because you are using the older 3D viewer called 4.15. Newer objects will not appear in the old viewer, and you will need to switch to the newer 4.5 viewer. You can do this from SETTINGS in 2D. Select 'Do NOT use Ecdesign 4.15 viewer and then restart Ecdesign 4.