please need some tips for rendering a light bulb

[miohn]

Hi,

need some help please!

I need to render a lightbulb with light emitting from insight a glass of course.

Everything is fine until I activate the light-source (meshlight, arealight, blackbody does not matter)
inside the glass-bulb (thickness via cloth-nurbs/ clear glass material/ fake shadows on/of does not matter)
My rendersettings: 16.000 max. samples/16 spec depth/ 0.5 caustic blur/1.25 filter size 1/ Mio lightsamples
but whatever settings I try - I get massive noise in beauty-pass, the corresponding light-pass and refraction pass.

What the hell I'm doing wrong here?
How do I need to set this up to get it noise-free?

thanks much!
Mike

[bepeg4d]

Hi Mike,
not the best condition for Path Tracing kernel, you can try with GI Clamp at 10, and v3.08test6, but better to switch to PMC kernel for this kind of scenes, in my opinion.
ciao beppe

[miohn]

thanks beppe,

will try PMC.
But why going back to Version 3.06? I'm now working with 3.07R2

regards
Mike

[bepeg4d]

Hi Mike,
sorry for the typo, I was meaning 3.08test6.
I have corrected the original post.
ciao beppe

[miohn]

Hi,

PMC with a 7.000px image blows up rendertimes immeasurable and
does not make a big difference.

so in the end: glass and light is a combo which octane cannot handle
without producing massive noise. Too bad!

regards
Mike

[milanm]

Hi Mike

I see that you are using adaptive sampling with lightpasses. Please note that there is an issue with AS that is limiting the samples for the layer and light passes to Min samples value, resulting in super-noisy passes.

Regarding rendering light bulbs I did a spot a long time ago ( in V2 ). I used directlight and AO and rendertimes were about 2min max on two 780s. I'll try to dig up the scene files to see what exactly I did if I can, but I remember I used lights OUTSIDE the lightbulb because back then we couldn't have the light behind the glass invisible. Also it was a macro shot and the bulb was exploding so I had a ridiculously high amount of refraction bounces and crazy dof to deal with in 1080p. I also used layers ( in a first test version that had them) to separate and denoise in post the bulbs in the background ( 720p for out-of-focus background ) and an animated render region for the hero bulb on top to denoise it a bit more.

I hope that helps.

Regards
Milan

[miohn]

Hi Milan,

thanks for your answer!

I did that finally in Post (rendered images without glass etc.)
and composed all together in PS.
The result ist not as realistic as I would have liked, but for that
purpose it was o.k.

Thats a Job better done with Redshift I think
Maybe next time...

thanks
Mike