Any other tips to make ForestPack render faster - in animation?

[Morne]

Hi guys

So besides setting the object subdivs to 0, what else could I do to make it speed up? Does forestpack have some clever setting somehwere that I don't know about for the materials maybe? Currently I'm using the stuff from the built in library - as is. (but with object subdivs on 0)

I don't really want to go the route of VRay environment light and fake AO for the shadows, so any other tips are welcome!

Amount of plants? Think "rain forest"...

[Macker]

Turn off filtering on the alpha maps.

[super gnu]

better to use "stochastic" for the opacity type than turn off filtering. if you disable filtering your AA engine needs to do loads more work to reduce shimmering. you could use "clip" for opacity, which would be faster, but you have a similar issue as with turning off filtering, since the AA engine would have to clean up all the sharp edges of your leaves.

[Morne]

better to use "stochastic" for the opacity type than turn off filtering. if you disable filtering your AA engine needs to do loads more work to reduce shimmering. you could use "clip" for opacity, which would be faster, but you have a similar issue as with turning off filtering, since the AA engine would have to clean up all the sharp edges of your leaves.

How does this affect flickering?

[super gnu]

in what sense? are you referring to GI flickering or AA shimmer? with aa shimmer, switching from "normal" to "stochastic" for the opacity maps should speed things up without increasing aa shimmer. clip on the other hand will speed things up even more, but introduce much sharper edges on the tree leaves ( like turning off filtering) so more shimmer for the AA to clear up. since the AA system does a lot of other work too, you will likely find its slower to render, once youve cranked the aa/noise thresh. to compensate for the increased shimmering.

so for animation, stochastic is a good compromise.


if you are referring to gi flickering, and are dealing with perframe gi (i.e. not flythrough, precalced stuff) then it wont make much (any?) difference. only solution there is to use brute force, or fake it using a domelight or ambientlight with dirtmap for the trees.

im not sure why you dont wanna consider that option.. with a bit of tweaking you can get something that looks great and renders much faster than brute force.

[Morne]

Sadly in the 8 forest objects (each containing 3 to 5 different plants), none of them have any opacity maps!
Any other tips?

[3DMK]

Sadly in the 8 forest objects (each containing 3 to 5 different plants), none of them have any opacity maps!
Any other tips?

You could try setting the max bounce of ray-traced reflections down to 2 or even 1. This should make a difference to a scene that is mostly trees with lots of ray-traced reflections.

Cheers
Jamie

[Lupaz]

I believe turning off filtering for the diff maps works.

[super gnu]

again, as per the opacity map, any reduction in filtering of maps will result in more high frequency noise in your frames. this will require the aa engine to do more work to remove shimmering in the sequence..


you could try optimising your tree models? when you use the typical 2-3 million poly itrees or whatever for large forests, you are rendering a crapload of unnecessary detail. try reducing the number of leaves for trees you dont get close to, delete all twigs etc, but make individual leaves bigger, so the apparent density is similar. this will save you ram and aa /gi /shadow /reflection samples.

[Morbid Angel]

You might want to consider turning off reflection on the leaves (will speed things up a lot) specular is often enough.

[Lupaz]

again, as per the opacity map, any reduction in filtering of maps will result in more high frequency noise in your frames. this will require the aa engine to do more work to remove shimmering in the sequence..

I never noticed what you're saying. I don't get any kind of perceivable noise, nor notice a substantial increment in rendering time due to aa "overload".

[super gnu]

we might be talking about a subtle difference, it depends on the scene. it might also be that your aa engine is already having to do so much sampling on the geometry details, that you get the unfiltered textures cleaned up "for free" (now that i think about it, this could mean you -do- get a speed up from disabling filtering in those circumstances.. hmm!)

-however its clear that removing filtering sharpens textures. sharper textures are more prone to moire effects and grain/shimmering when viewed at a distance. since vray always tries to clean up noise in an image using aa unless its otherwise been cleared (filtering or secondary ray subdivs) , down to the specified noise threshold, more moire and grain means more aa samples.

id also note im pretty much specifically talking about animation here.. differences in visible noise in a static image really would be negligable.


its also clearly noted in the vray help files here:

http://docs.chaosgroup.com/display/V...ymodeparameter


look at the paragraph describing the "clip" opacity mode:

"Clip opacity. Because the opacity map is forced to either full black or white, the result is sharp. The render time is very good, but the increased sharpness can increase flickering in animations"

[Lupaz]

id also note im pretty much specifically talking about animation here..

Me too. Animation.

It may be a case by case thing. Overall, I had good results by removing filtering on the leaves diffuse maps.

[h3d]

Have you tried using the LOD in the newest FP build? I have not tried this personally but I would think it would help in calculating "rain forest" amount of objects.

-Greg

[digitarch]

we´re also creating a landscape camera animation with forestpro forests - when using the new stochastic opacity mode (much faster with our scene now!) for the opacity mapped leaves, do I keep the default bitmap filtering enabled or shoud I disable now with stocastic? Also, what about the bitmap blur, keep to 1 to minimize hard edges?
Matthias