Emissive material suddenly messed up

[rp1]

D5 Render Version: 3.1.1

Graphics Card: RTX 470 laptop

Driver Version: 617.14

Issue Description: Emissive light looking messy and appears to be pulsating on live view. Final render looks the same as the screenshot. This was not problem on other project so im unsure whats causing it

Screenshots/Videos Description:
i

Steps to Reproduce (optional):
Unsure whats causing it. On other project the emissive does not behave this way.

[visualplus]

hi,
please check below comments :

1. is that object which is used for emissive intersecting with ceiling surface
2. that emissive object is on even distance around cove light space or is it far inside from bottom ceiling outer edge. ( bcoz its not seen in front angle )
3. can u share scene, so i can check on my end.
   if u found this helpful please mark as solution.
   thanks

[s.bernard]

Looks like a geometry problem to me as well

[rp1]

hi ! i managed to solve the issue. there was some models that are very far away from my scene (entire city block worth of building massing basically)

i deleted them and the lighting started rendering normally.

altho i have resolved it, i would like to know how come that happens! if you dont mind ! so i can avoid further similar situation like this