Hi,
May I know how to solve these artifacts on my final render? never facing this before…
where are artifacts being encountered? Not very obvious what you actually mean. The black lines? Its a bit to abstract - at least to me.
Or the posterization (banding) in the ceiling? In that case you need to add noise. You can try to save in a higher bit depth format (32bit float like EXR, or 16bit PNG), but you pretty much need to add noise to get rid of it.
The posterization in the ceiling
add noise? yes, this images I save in tiff 16 bits
Noise/grain is pretty much the only solution to banding. The posterization can occur at many different levels-- in the file format (unlikely at 16bit) in the display, in the display LUT, etc. Noise/dithering is really the only way to hide it. If you are using a denoiser, perhaps don’t… or add noise back in.