Photon kernel + octane daylight/sun = flickering animation

[epicmind]

Hi,

I was rendering out an animation where I'm in need of caustics and noticed the sun is flickering in size/intensity in the specular reflections. Any reason for this? Should I avoid using a sun and create an area light that's small in radius, etc? I'm using the Photon kernel.

Thanks!

[ShivaMist]

You should post your scene so the devs can take a look I’ve also encountered the issue but i don’t have any scène file to provide.

[epicmind]

Hey thanks for the reply. I'd love to share with the developers - but I cannot post the file in a public forum as it's client/NDA/based project. I might just create a generic version and post this later if I can.

So you've gotten the same problem? In my scene the sun is moving across the sky, playing with shadows on a metallic object. The sun's specular reflection varies frame-by-frame quite a bit. I am currently exporting 2 test render animations 1 with a octane-sun/inifite light, and one with a very small area light (caustics are better with the octane sun in my initial tests). I'll report this back when done.

I'm kinda new posting here though been using C4D for years lol. I just upload the c4d file? What about materials, etc?

[elsksa]

ORBX file.

But for those who can't download them, reproducing the issue on a basic scene and posting screen grab + repro steps will suffice and greatly help.

[epicmind]

Hi, so I did a very generic test. This is a metal tube with an octane daylight/sun light source alongside a couple of area style lights. You can see the animation link here, the specular "sun" flickers non stop, like a candle would.

Video: https://vimeo.com/834237541/f15e6dcac2

I uploaded the ORBX file of the above animation here: https://we.tl/t-PpDB1yx1ru

I did another test without an octane daylight/sun but with tiny area lights, they don't appear to flicker, BUT the caustics aren't comparable. Any ideas what is happening?

Thanks!

[epicmind]

Just following up - anyone have any ideas? I see the ORBX has been downloaded several times, but no input. Should I contact Otoy support for insight perhaps?

[elsksa]

It would be ideal to have post-fx disabled. At first look, it doesn't appear as flickering but reflection changes due to the shape of the asset and camera movement.

I did another test without an octane daylight/sun but with tiny area lights, they don't appear to flicker, BUT the caustics aren't comparable. Any ideas what is happening?

Both (should) produce the same expected caustics result when appropriately setup.

[epicmind]

Thanks for the reply Elsksa.

After doing more testing, it appears I needed many more samples. At around 1200 for an HD animation output, the flicker was 90+ percent gone. Anything less than that, it got worse and worse. At 600, it was every few frames. Sadly, ever since I'm exporting animations, Windows is crashing and forcing restarts now... which stops my render queues. So frustrating. Latest version of Octane, C4D, and Nvidia's drivers (non gaming).

[elsksa]

Windows is crashing and forcing restarts

A straight computer restart? From "rendering" to a brute-force computer reset (I guess black screen)?
No blue-screen/error code? What about hardware and heat (or cooling, should I say)?

[epicmind]

Hey,

It happens while rendering animations. Usually overnight, so I do not see the screen. I wake up to a restarted PC, with the render being stopped at some point.