Grass noise in Animation

[RonAcoud]

Hi Everyone. I have an issue regarding an animation with grass. I am using Vray, multi scatter, and a igrass scene(which is a file that is pre built to use randomized grass..fantastic looking stuff ) However, I am having an issue with crawling in the animation. I have done numerous test in AA and materials and I cant seem to figure this one out. Any suggestions would be great, especially if you have resolved this issue before. The guys over at rendering.ru, in a forum, said this was a Vray issue.

Things I have tried that didnt improve:

 

• increased subdivisions in reflection/refraction
  
• AO off and on
  
• Area instead mitchell-Netravali
  
• more baked frames on the IrrMap along the path
  
• a default vray mat gray on the grass
  

 

I will say that when I export the video out at as an mp4, the compression helps to blur the grass. But of coarse quality is lost over all with too much compression and whats the point.

 

Ron

[Nic H]

it's an antialiasing issue - but you don't show your antialiasing DMC settings....or a rendered frame!

 

never use a sharpening filter (try area or quadratic)

try upping your DMC to something like 1/10 - default is 1/4 - and lowering the noise threshold in the sampler to something like 0.005

turn off that AO in the GI - i doubt its doing much except adding to your render times

render a zdepth and use this to add a tiny depth blur of a pixel or 2

 

this should solve it - or make it loads smoother

[RonAcoud]

DMC is the standard 1/4. My hope is I can resolove tis without going to 1/10 because of frame times.

[Nic H]

yep its a difficult situation to resolve - high AA, depth blur and a softening filter are the best way to clear up that noise.

 

if i was you i would turn off glossy reflection as well - do you really need it on a animation frame?

 

why not untick 'trace reflection' and just get the highlight? no one will notice and it should be marginally faster and look very similar.

 

also in mulctiscatter you can make it falloff based on camera distance so you have less detail in the background - that might be worth looking at - iv not used it myself but it would probably be useful in this situation to help reduce render times.

[RonAcoud]

where is the "glossy reflection" you're referring to?

For the Multiscattter, if you look close I am using the clipping plan of the camera at 240 feet. It renders at a reasonable time right now at 1280x720.

[Nic H]

in the material - reflection glossiness / glossy reflection

[RonAcoud]

wow the DMC 1/10 really helps bring it to no noise at all but doubles the frame . Do you have a good resource or tutorial for rendering(the grass) on a pass or layer?

[Nic H]

yep its expensive...

also i noticed your vray sun was set at 3 subdivs? this will add noisy shadows

 

ill try make a little file for you to show vray matte object useage

[Tommy L]

You could use a blurring filter for animation. Try adaptive subdivision with area filter instead of DMC. It will keep your render times down and you wont get as much noise in motion.

[RonAcoud]

That would be awesome. Thank you nicnic