Just fell on this via google so I’m not sure if it’s known and discussed elsewhere by now. Apologies if it is.
This does seem to be a 5.1.0 bug with Build Geometry specifically. It’s causing any and all actor BP components to vanish from the editor, not even DefaultSceneRoot on an empty BP is spared.
With a fresh install and default settings:
- Create new blank project
- Create a new actor BP and add literally anything (cube mesh, box collision, wtva)
- Compile/save and Build Geometry
The components completely vanish from the level viewport (the BPs themselves are still technically there) or as mentioned if it’s a blank BP, the DefaultSceneRoot icon also disappears.
It affects other classes too. Cameras vanish from Character BPs for instance, and no longer show a camera preview when selecting the BP from the Outliner, indicating it truly believes there is no camera component and it’s not just a visual bug. Lighting ofc won’t build if it thinks there’s no geometry there to begin with.
Temp fixes:
- Compiling the BPs again
- Reloading the level or restarting UE
- The game itself is unaffected when you play it (as auto recompile is on by default)
It’s as if Build Geometry is somehow compiling empty BPs which then get reflected in the viewport. Nothing else seems to cause it for me, just Build Geometry.