translucent glass huge rendertime

[fLuppster]

I dont need help for creating the translucent glass, i could need some advices how i can optimise the render speed in my scene.
If i click render, at the moment corona is precalculating about 5 minutes, which is way too much. I already checked if there are any overlapping/superimposed polygons, but the meshes are clean.
Could it help to place a portal light? (I guess not, since they are for small windows only, and my facade is completly open)

Do you have any idea how to improve the rendertime?


The setup looks like this:


green lines are translucent glasses
blue lines transparent ones. (obvious)

There are like 4 IES lights in the ceiling and one normal HDRi outside.

the profiled glass is built like this:


reflection channel:


refraction channel:

[fLuppster]

Okay, it seems it was a C4D bug. I copied everything into a new scene and it worked again. ;)

[fLuppster]

Well, i have rendered the scene for 53 min now. (16 passes, progressive renderer, standard performance settings)
It will be an animation, so i really need to reduce rendertime here. The limit for 1 frame should be 1 hour.



Do you think it is possible to optimise this scene to reach that goal?
If yes: how? ;o

[FrostKiwi]

Do you think it is possible to optimise this scene to reach that goal?

Can you settle with glossy refraction instead of translucency? Translucency bounces rays inside a Volume, which is incredibly costly and always has been tried to be faked many many times in the past. Like SSS precalc. In corona we don't do that anymore. It's real traced translucency.
If you could settle for that, then the render would just fly compared to volumetrically sampling a whole freaking wall with 60% coverage of the frame.

Really like the aesthetic :D

[fLuppster]

Well, translucency is deactivated. ;) I posted the material setting. Its just refractive glossiness.

[Juraj]

Yeah, it's regular frosted glass, which is total rendering nightmare. Last year I had big animation in Vray done, where everything was optimalized to inch, almost desperate stuff. Everything except frosted glass.... I almost lost sanity. Researched every shit under sun.

Glossy refraction is also far more expensive than translucency in every test I ever did.

The only possible solution for scenario like this, is fake frosted material. Unless you can see properly depth (some item is right behind, little bit your case too since you can see the glass structure repeating...), blurring in post-production refraction channel is one possible way,
though I don't know how well that works in animation.

There really ought to be a separate shader to do just this in rendering packages. Like Vray's FastSSS, only semi-fake frosted glass focused. Because, damn it, it's only scratched glass, it's hillarious enough we have to create that effect by blurring refraction instead of simple surface microbump.


Also this is the scenario where filtering would truly help, but adaptation would do little since it's complicated all-over. Which is why both belong to future.

Sorry not being helpful, just feeling your problem :- )

[maru]

Do you think it is possible to optimise this scene to reach that goal?

Can you settle with glossy refraction instead of translucency? Translucency bounces rays inside a Volume, which is incredibly costly and always has been tried to be faked many many times in the past. Like SSS precalc. In corona we don't do that anymore. It's real traced translucency.
If you could settle for that, then the render would just fly compared to volumetrically sampling a whole freaking wall with 60% coverage of the frame.

Really like the aesthetic :D

I would rather say that translucency (not volumetric absorption/scattering) should be much faster than glossy refractions, though I may be wrong. I will try to do some tests later.

[fLuppster]

Okay, thank you guys. I'll try it with translucency and maybe even some opacity.

[romullus]

You may want to check this topic: https://forum.corona-renderer.com/index.php/topic,4960.0.html
Very similar case to yours.

[fLuppster]

Thank you so much! Thats the solution i guess. Great setup.


Just 30 seconds rendered.