Antialiasing for Animations with Proxy Trees

[tammo]

I have to render several long animations with a lot of vegetation and run into some antialiasing problems with Vray proxy trees.

I tried to render with Adaptive DMC set on 1/6 with adaptive amount:1.0 and Noise threshold:0.01 and the "Quadratic" Antialiasing filter.

The GI is working fine with Irradiance maps precalculated with the "Use Camera Path" option.

All Buildings look good but there is a lot of noise on the trees,
especially in the distance.

I tried to remove the noise in after effects, but its simply too much.

Has anyone run into the same problem?
I cant simply raise every setting because of the rendertime and upcoming deadline.

Maybe using the "fixed" type image sampler will help?

Here is a small cropped area from the HD Version,
i cant show much because of the NDA:
www.vector-film.de/AAproblem.wmv

kind regards,
tammo

[joconnell]

It's a tough one alright - softer anti aliasing, motion blur and rendering at higher res and scaling down are the only things you can do - a lot of the time it's that the leaves on the trees are so small they cause pixels to flicker on broadcast tv. Try rendering a velocity pass with your renders and use post motion blur - it might smudge the detail enough to solve the problem (although your renders might not look as nice).

[trick]

I mostly use 2-8 or 3-8 !! I guess 2-6 or 3-6 should do too. Just try and report.

[tammo]

thanks, i will try to raise the low value, sounds like a good idea.

I tried the velocity pass with post blur in after effects,
it works very well for the fastmoving objects but the trees in the background are not moving fast enough to get enough blur.

[Neilg]

I usually go 1,12 or 1,8 when doing landscape stuff. 6 is never really enough.

[trick]

I tried 1-100 once, but that really does not take away small mesh detail flickering. You really need to go subpixel for that (or render higher res and scale down). A high max. value removes flickering from noise (coming from glossies for example) and things, mostly coming from (too) low subdiv values.

The problem with small mesh details (around the size of a pixel) is that they can be there in one frame/pixel, but not in the other frame/pixel because you're sampling goes not "lower" then 1 pixel. You can upscale your image, or go the subsampling route (min.value 2 takes 4 subpixels, i.o.w.make image twice as wide and twice as high). In my experience rendertimes for subsampling are faster then with upscaling.

[3DMK]

Z-depth map to try & blur the background trees a bit

Have you tried using a Z-depth map to try & blur the background trees a bit??
This way eve n if they are moving slowly they are still blured enough to loose the flicker. I have tried this method & it works OK depending on your scene.


It's also important to remember to lower your noise threshold on the AA image sampler as well. I have found the default value for the DMC of .01 will let a lot of noise go un-sampled. To force the AA sampler to reduce the noise more I turn the threshold down to .002. This will also reduce any texture flickering as well.

Cheers
Jamie

[natty]

I think you need to look at all your settings not just your AA, what you are seeing there is movement of noise so you need to fix that, you will need to go very high with your noise thresholds ect ect ... there are more than one factor here to consider....

[tammo]

Thanks for your help.
I made a new try with 2/6 as suggested and the noise is almost gone.
I can remove the rest in after effects with "remove noise" (timebased) and some vector-motionblur.
Unfortunately the rendertime is now at almost 40 minutes per 1280*720 Frame.
1/6 was more then twice as fast.

I will try 2/4 next but i dont think it will work.

here is a very short clip with the 2/6 settings:
www.vector-film.de/AAtest-2-6.wmv

kind regards,
tammo

[trick]

...Unfortunately the rendertime is now at almost 40 minutes per 1280*720 Frame.
1/6 was more then twice as fast...

You should compare 2-6 with rendering the same image 2560x1440, which would result in almost 4 times slower. Next to that: quality would be worse since there is no downsampling algorhythm as good as the DMC sampler does with AA !!

[BLADE]

@tammo

Did you solve the problem with the flickering trees? If so, do you mind to share your solution? I have exact the same problem here and rendertimes are killing my budget and deadline.

Greets
BLADE

[joconnell]

You've got two issues with them - general vray noise and then you've got pixel crawling which is just a limitation of broadcast tv - the noise is going to be dealt with by your aa - the pixel crawling has to be softened unfortunately. Try a soft anti aliaser like video or use a motion blur that "smudges" the image - Try something like reelsmart motion blur in after effects using a vector pass rendered from vray.

[tammo]

Yes it was solved by using 2/6 as suggested and the noise was almost gone.
The rest the noise was removed in after effects with "remove noise" (timebased) and some vector-motionblur.
On some of the scenes i used 1/8 and reduced the adaptive amount from 1,0 to 0,9.
That was faster but also a bit noisier.

[trick]

Noise caused by low subdivs can mostly be removed by upping the Max value.

Noise caused by texture details or too strong bump maps (causing Moire patterns) must be solved by image filters. Personally I try to avoid image filters whenever I can, even in animations, by just using the right textures and values for bump, diffuse, etc. This makes for crisper images and with faster camera speeds issues will be removed by using mtion blur...even in post...

Flickering caused by small details however only with higher Min values, because if 1 they are only there in one frame and maybe not in the next. With higher Min values these details can be traced back by subpixel sampling.

[flino2004]

I did an animation few days ago with trees without problems.
AA filter was "area"
dmc 1-10
Irmap preset medium animation with 75-25
LC 5000 subd. filter fixed
Precalculated GI using Camera Path.

Noise Thres.=.003