Night Scene Tweet

[coilbook]

Hello,

Can Octane handle this without noise? I think it struggles with night scenes and reflections with roughness and DOF.

Should all lights be set to the same sampling rate? Can we have automatic/dynamic sampling rate where the system/AI detects problematic lights and gives them more samples?

Thank you!

[elsksa]

This is tricky for nearly all renderers. Optimization and lighting tricks (such as hidden/invisible "motivated light technique" lights) are key.

The answer to (probably) all your sampling related questions (and misconceptions) are here: Octane Sampling Guide.

[frankmci]

Unfortunately, noise is going to be an issue whenever you are ray tracing with large numbers of light sources, regardless of the render engine. In a scene like this one, however, a large fraction of light sources do not need the full ray casting treatment, greatly increasing render efficiency.

Without seeing the actual scene file, it's hard to say, but I'm guessing that the vast majority of your building/window lights can have very low sampling relative to your street level lights. Most of them probably don't need Visible on Diffuse, Visible on Specular, visible on Scattering Volumes, or Cast Shadows. Unless those windows are directly illuminating nearby geometry, they just need to be self illuminating, which is very fast and doesn't use up your sampling budget.

It looks like only the two buildings on the right have actual geometric interiors. Even there, you may want to cheat a bit and have two sets of lights, one set to actually illuminate the interior, and another set for camera visibility. With a little creativity, you can probably get away with only a hand full of illumination light sources that need ray tracing. You might also consider baking those illuminated interiors.

You can also do a neat little trick with car headlights where they don't actually cast illumination. Instead, you can use a flat plane just above ground level in front of the vehicle with a transparent, self illuminating texture on it, that again does not need Visible on Diffuse, etc. turned on. That doesn't work on Hero vehicles, but when you have masses of distant moving cars, it can look great and render super fast.

I hope that gives you some ideas to explore. Good luck.

[elsksa]

You can also do a neat little trick with car headlights where they don't actually cast illumination. Instead, you can use a flat plane just above ground level in front of the vehicle with a transparent, self illuminating texture on it, that again does not need Visible on Diffuse, etc. turned on. That doesn't work on Hero vehicles, but when you have masses of distant moving cars, it can look great and render super fast.

This (is joining my early reply). Actually quite standard and definitely recommended.
The goal is to make it look photo-real, not to simulate the reality (the wrong approach with these tools, i.e. renderers).

[coilbook]

Thank you all!