QMC too noisey

[alfienoakes]

I have an animation we are piecing together, similar to one we did a while ago. They are short bursts of animation, with a still at either end.

 

I am using IR and LC as they are internals and this mix produces good results for int animations, in a good amount of time per frame.

 

Problem is, I cannot get rid of the noise in the more ambient areas.

 

I think it is from the QMC side of things.

 

My current settings are as follows:

 

Image Sampler: aQMC 1/4

AA Mitchell Netravali

GI = IR and LC

IR - MIn Max -3/-1 Hsph/Interps 70/20

LC - 1500 subs / 50mm Samp size. scale world (small model) passes 4 Interp samps 10

QMC sampler .85 AA / Noise thresh .005 / min samps 12 time dependant

 

Now the animation quality is good, but the noise is there.. see the attached images.. If I lower the noise threshold, I can lose alot of the noise, but the render times go crazy..

 

Andy help would be great.. cheers

 

Andy

[FlytE]

On first glance my initial suspicions are that you might need to reduce the noise threshold in your qmc settings. This of course will up the rendertimes though...

[alfienoakes]

Hey Andy..

 

Yep, this sorts it out a treat, but I go from abou 20 mins per frame, to about 1 hour.. I am pre calcing the IR map, every 5 or so frames, so it does ease things a little.. but it is still a bit too much..

 

I suppose I could pre calc the LC as well. Its only a 60 - 100 frame animation, and movement is fairly fast. Could I push my pre calced frames to every 10th say..?

 

And.. if I check store with ir in my vray lights, will that speed the animation up as well..?

 

cheers

 

Andy

[FlytE]

Possibly. I never normally store my lights with my irradiance map, but I would always precalculate whatever I could before I render including lightcache. Someone I know renders their irradiance map ever 4 frames but i have never encountered any problems rendering it every tenth frame so thats my recommendation.

[Fran]

Andy, you might try using Adaptive AA instead of the QMC for this situation. And put the noise threshold back to .85 to see if it works for that setting.

 

Is that rendered with V1.47? I haven't used 1.5 yet, so I don't know what options are available anymore.

[alfienoakes]

Hi Fran,

 

Yep its 1.47.03..

 

I tried it with with slightly different settings and got much better render times.

 

I changed the Inter Hshp down to 50 / 20, which has worked well for us before, left the Image Sampler as aQMC 1/4, and the AA as Mitchell Netravali.

 

But we did change the min samples in the QMC down to 8.. Then ran it with the noise threshold at .002, and voila..!!

 

Sometimes my workflow feels like I have gone in a circle, and not changed anything.. then the smallest change seems to make the difference..!

 

Thanks for input.. will post some scenes once they are done..

 

Andy

[Christopher Nichols]

I am a huge QMC AA person because I do a lot of glossy effects, motion blur, etc... all of which are better with QMC. If you are using a Linear workflow, you will need to lower your noise threshold just like you did. Also, make sure and set your Adaptive amount in the QMC from 0.85 to 1.0, which can help you be more efficient, and for some extra quality, don't be afraid to raise your max of the QMC to 10 or higher.

 

However, I am with Fran on this one. Considering what you are trying to render, your renderings would be a lot more efficient with Adapative Subdiv AA, maybe with 0,2 as a setting. Adaptive works really well for smooth diffuse surfaces like large white architectural walls.

[alfienoakes]

Cheers Christopher..

 

I will try these out today, see what I can get render times out at..

 

Just one thing, what exactly do you mean by this:

 

"and for some extra quality, don't be afraid to raise your max of the QMC to 10 or higher."

 

Do you mean the sub divs..?

 

I will post some of the images in the finished work section today hopefully, try and show people how we are getting on..

 

Thanks for the help people..

 

Andy

[Christopher Nichols]

Just one thing, what exactly do you mean by this:

 

"and for some extra quality, don't be afraid to raise your max of the QMC to 10 or higher."

 

Do you mean the sub divs..?

 

 

I mean raise the QMC max value in the AA to 10 or higher

[kaimanino]

adaptive amoun : 0.85 min samples : 16

noise threshold : 0.002 global subdivs multipler : 2