Static mesh visibility problem


We’re currently have problem in a project (public VR demo ttaking place on monday…). All the static meshes show ok, lightmap is ok (even though rendreding is looooong since we have a lot of objects in the map, about 26k, most of them instanced, so it make 384 base meshes ).

From time to time, and only for a series of static meshes (instanced and parent mesh), this very static meshes (roof tiles) do not show anymore on screen. They still are physically in the scene (actirs are “here”) though not visible (they are tagged renderable in game and visible in scene). Weirdest thing is that they still reflect light (radisity effect, white walls near the tiles are slightly colored due to the color of those tiles reflecting ). The “roof tiles” material is checked double sided since those tiles have only a visible face facing on the visble side. Normals are ok (I am in charge of the modelling process and I pre-load and check every scenes on my station before delivering them to my colleague). Light map resolution if ok (I render some parts of the scene from time to time as well).

When this problem suddenly appears it seems we have no other choice but deleting the map, emptying the cache, the “save folder” and so on… It’s no a satisfying way to do things though and pretty time consuming

Any idea on this problem ?

Thanks a lot for you help on this urgent matter !!!

Are you positive this isn’t just an occlusion issue?
(the object is too small to be rendered, or is covered by another object?)

Thanks for the answer.

Not sure at 100pcent if it’s a bug or something else. Occlusion could be an answer but I do not have this problem on my station. it only occurs when integrated in the full project (I do not have the full project on my computer, only the project director owns it), so it could be settings related.

The project director has the same problems with tiles on different maps or submaps even though those tiles are not the same models and do not share the same textures nor anything else.
Since i am not (yet) an expert in UE4 settings, I was also wondering if it could be related to a camera / character position settings, the tiles being on top of building and not 100% visible from the ground but only for the edge of them…

It has to be a parameter. Even if it’s occlusion related I do not have this problem and he encouters it… Maybe the lightmap size of these assets (i think i hqve checked this already but worth checking again) ? The mesh does not have overlapping UVs though (I take a great care to UV mapping)

My colleague just informed me he added a visibilty volume in the scene. Could be this. He is checking.