shuttering of forest in forestpack/multiscatter

[thomes]

hi

we have here big forest scene with much of forest made in forestpack (but we had same "problem" also with forest made with multiscatter)
there is a camera flying over and we rendered with prerendered lightsolution irrmap/BF loading.

the mapped landscape is good, but the forest is shuttering.
rendered dmc 1/4 without AAfilter with default dmcsampler settings

what would you recommend ?
-higher dmc subdivs
-adapt. subdiv as image sampler
-AA filter
-reducing noise threshold in dmc sampler?
-other idea?

thanks for ideas
thomes

this is a small part of a fullhd picture

[joconnell]

AA and motion blur are really heavily needed for camera moves near trees - even if the detail is rendered really solidly and correctly, you'll still get part of a tree that's less than a pixel and so a slow moving camera over that will make it look like a huge dancing field of noise. Softer aa filters help (I'd be inclined to do that in post with a blur) and definitely motion blur. Atmospheric haze can reduce the contrast of edges so that'll make shimmering less apparent but your big thing is definitely AA. If you've got a static camera as above then turning off the time independent switch will lock the pattern of your noise. It looks better on static cameras since it won't "dance" but on moving cameras it can look like dirt on the screen so time independent ON is better there.

Higher AA, AA filter on to blur things.

[thomes]

well big thanks for first thoughts jo,

any recommendment for rendered AAfilter to blur? area, video,blend or a vrayone? we tried in post with some of the AE blur features, but it looks the same noisy but blurred )

[joconnell]

If it's HD people have found decent results with quadratic. I like area as a general filter personally as it'll smooth some edges without having any major speed hit on the render (there is still a slight hit, but less than other AA filters) and it's still sharp enough to give you the option of further blurring. Some of the other filters are very blurry so when you have that burnt into the main 3d render you've no options to go sharper afterward. Ideally better AA and turning off time independent will lock the noise in the particular render you have above so you won't get as many visible issues.

[thomes]

thanks jo,

as i understand spot3d help, the time independent "checked" locks noise. wrong?

thanks for help
thomes

[joconnell]

Nope, you're exactly right so it's a bad thing for moving camera footage especially, might be more visually pleasing for locked cameras.

[trick]

Rendering full 3D detailed trees with an AA min value of 1 always gives flickering results because the details are most probably smaller than one pixel, which will make it impredictable what color that pixel will be in the next frame. Subsampling with a min 2 value makes a huge differencee.... so just try 2/6.... Filtering the small details is completely unnecessary ... unless your leaves have a micro black/white checker pattern

[thomes]

thanks for your help boys,

we did some 4 frame testrenders. DMC 2/4 was also not that good. what gave good results was DMC 2/9 and lower the noise threshold to 0.002.we also took the area filter 1.5. as i understand these picture filters smooth/blur areas over more pixels (for some of the filters up to i think 25 pixels). i´m not really familiar with image blurs/sharpeners, cause most of the time we render without. but this area filter is quite okai as jo said, it does not make the rendering too blurry.but you have the cost of rendertime...

[joconnell]

Area is okay. I like the look of mitchell but it's sharp so it'll make your problems worse, catmull makes everything look pixar-ish. Video and quadratic are handy for flickering issues as they're soft but you might be able to do a test in post and see can you replicate them with a gaussian blur - you'll have more flexibility if so and might save some render time.

[Itoosoft]

If that helps, i got nice results using After Effects->Remove Grain. Very helpful if you don't want to render again, or have not time to use high AA values.