Dropbox Capture

Steps to reproduce:
Zooming out of a small object it vanishes

Expected result: should show still when zooming out
Actual result: see video here: Dropbox Capture

Does your object have LODs

Open Debug model Lods

You will see that, mostly because you have only a single LOD , because of enforced Lod system , when zooming away your object is too much complex
Add less detailed LODs and it will stay in place
Monitor closely the debug model Lods/statistics profiler