Hello im not sure how to explain this issue. can someone please help. Here is the blend file. https://drive.google.com/file/d/1UDdb18_2mDb-YWzECdjKuvAT3At11YQo/view?usp=sharing
the issue is when you enter render preview near the ground floor railing on the wall.
if you mean that black thing on walls then it’s really weird. I have no idea what is causing it but i know how to fix it.
I’ve noticed your object have really weird scale (its almost 500 meters wide) when you scale it down the problem disapears
press ‘A’ to select all, 'S" then type value like 0.1 to make everything smaller. then press CTR + ‘A’ and chose apply scale.
you will also get rid of the camera clipping that way
I honestly have been having trouble understanding/using the units of measurement in blender. Im using Imperial, idk metric very well. But i was trying to define my edges in feet and inches and was getting unsatisfying results, but when i just used inches it seemed to work okay. But you say my scale is off. idk.
But that worked. Thank you for your help!