I didn’t change much in the settings for the lights, I changed:
in World Settings : static Lighting Level Scale → 0.2 (to have a smoother transition between the shadows)
Overriden Light Map res of the InstancedStaticMesh, in fact by default it’s 64 but i have a warning message when building who says “The total lightmap size for this Instanced… is large”. But if i reduce it, the problem is bigger and if i increase it, it’s just a very little bit better but OK at all and I have the warning message.
I don’t think I’ve touched anything else, I’ve done a lot of tests but considering the results, I’m back to the beginning.
I think I’m going to redo a new clean project before going too far in the game to restart on a healthy basis and see if the problem is still there.
Do you have any advice for creating this type of level(instanced mesh, size, light, lightmap, etc?) to avoid falling back into this kind of problems and gain fluidity?