Gi Animation Perfomance Tests

[samuel_bubat]

Hello,

I made two test animations, to see what´s possible..
5 Intel Q6600/XP32 machines were in use for both tests.
Please keep in mind, these animations are made to test rendertimes
under some more or less extreme conditions.

The first animation is a simple flight through a forest.
1000 trees, 3000 ferns.
Lighting: Direct light multiplier 50, env. multiplier 25, Max Logarithmic Exposure.

I used IrrMap/LightCache with IncrementalAdd/Flythrough Mode.
min/max rate -4/-2, 40 subdivs. Tresholds same as preset "Very Low".
The rendertime per frame was between 40-50 minutes in full PAL.
When using Incremential Add the Irradiance Map or Light Cache (not shure wich one)
needs ~20 frames to "get in groove", clean without flickering.
the animation was split up, an composed later. I used 20 frames for overlapping
to blend between the pieces. During these blendings a little
flickering in the background can be seen. But I think it´s ok
(Volume lights were made in fusion)

http://sorceress.netfrag.org/optix/s...ly_through.mov





The second test is a Sunset/Indoor Test with Dynamic GI.
Lighting VraySun/Sky. Max Logarithmic Exposure.
The new Vray animation mode/Light Cache was used.
min/max rate -4/-1, 60 subdivs, Clr. tresh. 1.0, Nrm. tresh 0.3, Dist. tresh. 0.2
For the final animation I used 8 interpolation frames. This blew up the rendertime a bit,
and gave me on some frames memory errors. Actually it would have been a better idea
to increase the subdivs. and decrease the interpolation frames, cause the prepass
with these settings did not take longer than 4-6 minutes.
Below the line, glossiness and softshadows, took most of the rendertime.
Rendertime: prepass 4-6 minutes, final image 15-28 minutes. So ~35min per frame
Rendersize was 720p (1280x720)
The carpet initially had displacement and the armchairs glossy reflections.
But I skipped both, it would have blown the rendertime.... so both look a bit dull.
In general I wonder how clean the animation turned out and how low
the rendertimes were for a dynamic, rather sharp Gi in a 720p resolution.
But there are sometimes big single blotches, I don´t know what´s the cause of them.
(Glow and a little color correction was added afterwards)

http://sorceress.netfrag.org/optix/s_dynamic_GI.mov





cheers,

sam

[vlado]

The spots in the second scene are reflections of the VRaySun; you can remove them if you tick the "Invisible" option for the sun.

Best regards,
Vlado

[katego5]

Bracken

How did you make that nice translucent material for the bracken? look really nice. And I dont see any flickering, and it allways flicker in my animations, So if you make a tut some day it would bee fantastic

[katego5]

Animation

I have tryed this tut http://www.spot3d.com/vray/help/150S...ials_imap2.htm but the outcome is not as fine as in the tut. And I followed it precise. I use max 2008 and vray 1,5 sp1. It looks like that if I have moving objekts http://www.spot3d.com/vray/help/150S...rials_anim.htm it seems that it has to be renderet out in layers. Isn't there a way of just render the animation with moving objects and without the flicker in one take???

[siliconbauhaus]

Very nice.....I cant render animations at that level due to old equipment.

Why did you use logarithmic exposure?

[samuel_bubat]

@katego5: regarding the bracken. The material is not really translucent. But I use a very
strong direct and environment light. This causes a strong color bleeding and indirect light
from the ground and surrounding leafs. A bit of glow and color correction afterwards
makes this effect even better.

To prevent blotches in general, in my opinion the Irradiance Map sample distribution
is very important. I made a post about that problematic, here.
http://www.chaosgroup.com/forums/vbu...ad.php?t=41558


@siliconbauhaus: I use Log. Exposure for several reasons.
1. It´s interactive. It has a little preview window (could be larger ) Once the preview
is rendered, I can adjust the exposure as needed without re-rendering the image just
to set the exposure. Vray has some similar tone mappings/VFB features , but I still prever Log. Exposure
because of the interactivity I ´m used with

compared to Camera Exposure it´s absolute supperior.
2. It has (for my taste) logical values like brightness contrast and midtones wich give me
neccessary control about every aspect of the image exposure, unlike camera exposure.
With a camera exposure you cannot balance contrast/gain against brightness. This
usually ends up with dummy lights to brighten dark regions of a room or changing GI
multiplier to prevent color bleeding in certain areas. This is all not neccessary with
Log. Exposure.

cheers,

sam

[siliconbauhaus]

That's quite a interesting concept. I didn't realise that log exposure actually worked with vray as I thought it was a mental ray only thing. I might try that out on my next project.