SS2 Flicker and Slow Renders

[Zach Gray]

I've got a fairly simple animation to render, and the frame times seem a bit long for what I'm doing. I'm not rendering the character on a separate layer since I want the GI/shadowing interaction from the environment.

I'm using a mid/animation irrad/brute force, 8core 8gb, vray standalone via qube, (if anyone needs the qube vray standalone python simpldcmd let me know) 1280x720. Displacement is broken at the moment, and it's averaging 45 mins per frame no motion blur!

Also, I need to kill the SS2 flicker, and I'm not sure how.

[vlado]

That render time is way too long for this scene. I can't really say what's wrong with it right away though - it would be best if you can get us some example to vraymaya@chaosgroup.com so that we can make some suggestions.

Best regards,
Vlado

[Zach Gray]

Uploaded a scene for your review. I think the DMC threshold was set very low, I'm experimenting with locking the threshold to the depth of 3. This has taken the frame time down to about 30 mins. I also turned down the Max Subdivision divisions to 3.

I'd be very receptive to any optimizations you can suggest.

[Zach Gray]

I can't kill the SSS2 Flicker. I increased the prepass to +1, which added 10 minutes to the frame time, but it's still there. The compression on Vimeo makes it hard to see, and you can only see it full frame, but uncompressed, it's pretty terrible.

[gimiky]

you'll probably have to modify your dmc settings, but have you tried brute force primary with light cache secondary? we haven't found any other combination (besides saving a per-frame irrad map prepass) that will dependably remove sss flicker.

[Zach Gray]

(Took a looong time to display, thought it was crashing)

Trying that now. Appears to be pretty slow, and my dmc max is 1.

[gimiky]

probably, but you shouldn't need to save the light cache.. just render it per frame.

[Zach Gray]

Wow... so my noisy 640x360 frame takes 10mins x4 to 1280x720 = 40 mins with dmc at 1!

[Zach Gray]

It was actually worse than I thought...

Brute Force / Light cache with 25 dmc subs was 6.5 hours for 1280x720
Brute Force / Brute force with 25 dmc subs was 4.5 hours for 1280x720

These did kill the SSS flicker though. Trying full quality irridiance map, hopefully, that will be acceptable.

8 core 8gb win 7

And the scene is really simple! Crazy, right?

[MoonDoggie]

I don't think it's your imap honestly. You probably could just Antialias is out of your frames in your original settings. What were your dmc settings?

[Zach Gray]

I think you are right. I turned the irrmap way up and it was still there.

On those first tests I posted, it wasn't that high. I was getting acceptable noise with Medium Animation irrmap and Adaptive Dmc subdivisions of about 4. Are you saying I should I increase the DMC subdivs to 8 or 12 or more?

[MoonDoggie]

Bingo, I would try something like min:2, max:8, and if you're using the noise threshold, you might need to lower that to compensate (adding rendertime) If your noise threshold is already low, keep it locked to the noise threshold. If your noise threshold is large (0.07 or so) I'd use a clr threshold of like 0.03.

If that doesn't work, use 2,10, then 2,12.

[Zach Gray]

I've tried all of the above settings, but the flicker on the SSS persists. Took the noise down to .005, samples up to 12.

Light Cache primary/Brute Force secondary just creates splotchy gradients even if sampling is way up and lightcache subdivs are up to 2000.

irrmap/lightcache still flickering in the SSS and leaking all over the place.

[Zach Gray]

...........

[MoonDoggie]

How does it look with the universal settings? (It's a sticky on the forum), takes a long time to render, but works for about everything and looks amazing.

ps. If you want to try the Brute force solution, brute force should be primary and secondary should be LC