This is the same 3D viewer I made long time ago and it's still not quite finished, but it's good enough to look at your fortress in 3D and share it with friends. The original viewer is still available for everyone, but now Server Subscription users have a gallery page with all their map snapshots, and also a button in the iOS app to save a snapshot. Links to view individual maps are public and thus can be shared with anyone.
The gallery has actually been available for some time now, so for those who already knew about it, the latest changes are the addition of previews and Delete button.