World tracking with Designer / delete assets

I tried many times world tracking with different devices, (Galaxy S7 or a Ipad4) but all I can see is choppy 3fps animation and the model doesn’t stay where I placed it…

Anybody have an experience to share on this?

Also, is there a way to delete assets (image/video/models…) in Designer beta?

It looks like world tracking works better with bright light condition, fewer models on screen and high performance profile on android.

Still wonder how to remove unused 3d assets from my list (It’s possible to delete image and movies from Media library but no 3d models).

I wonder if I might have a bug: