I searched the forum to see if there was a way to get it back and came across a couple of threads, but they're either out of date or don't relate to Mac:
(This path doesn't exist on my Mac. I did a hard drive search even for "eTeks" and nothing at all came up. . .)Where are settings (textures, 3D models, etc.) saved on the Mac?
http://www.sweethome3d.com/support/forum/viewthread_thread,9695
(This answer is only for the Windows versions.)Lost Imported Furniture after installing Paid For version
http://www.sweethome3d.com/support/forum/viewthread_thread,9683
Can anyone tell me if there's a way to retrieve all of my former furniture/textures on a Mac running OS X High Sierra? What is the updated path to where all of the Sweet Home 3D files are stored on a Mac?