Help with adding small glistening light effects without causing fireflies

I’m currently using a dark and overcast day HDRI to illuminate a scene of a car. The render is looking smooth and firefly free. However, I’d like to implement some faint lights in the distance, as perhaps these ‘lights’ came on a little early in anticipation for night. My goals is to get some nice spot highlights and glistening effects on the details of the car… minor but visible.

My attempt was almost successful, however fireflies were very present and it wasn’t worth sacrificing the render clarity. Is there any way to add these small glistening spot details without changing the whole lighting look?

Small lights like point lights shoot the light spherically around them. That means you need many samples to get a homogeneous result. Fireflies are actually only bright spots from caustics, but since the samples are too few, only a single bright point is calculated. Large area lights direct the light in one direction so that you get a good interpretation with very few samples. So you will not see any fireflies. The problem is that evenly spread scenes do not produce spectacular caustics. Your task is to adjust the size of area lights so that you get a good compromise between nice caustics and few fireflies. I would also combine a low sampling A.I. denoiser render with a high sampling without denoising in post pro because the A.I. denoiser detects the fireflies well but also washes the caustics.

Thank you for that, I’ll use the large area lights and play around with them as mentioned!

Last but not least you should definitely use LuxCoreRender. That is not what Cycles is made for.