Artefact EnvironnementFog

[pgenin]

Hello,
I'm working on a scene maya2011.
I'm using the NightlyBuild from 22 dec.
The lighting is an indoor hall with Raylight from outside
I created 2 RectLight (see fig) and set parameters light figs joined with the post.
I was looking for set renderSettings to get no Grain into the fog and i had thoses artefacts followed.. (VueCameraBug.png)
I rendered a renderElement (Zdeph) which is perfectly rendered (no artefacts)
May be someone knows this problem.

Please, if someone at Chaosgroup could light me about which value i have to set to have a rendering with no grain without having 7hours of rendering....
This frame was rendered in 1 h 20mn on an octocore and 16 g Ram ... where is my mistake?!

Thanks all and happy newyears with Vray

Pierre

I forget to join the log:
Starting "/usr/autodesk/maya2011-x64/bin/maya"

mental ray for Maya 2011
mental ray: version 3.8.1.33, Aug 20 2010, revision 124793
[2011/Jan/11|15:43:15] V-Ray: V-Ray for Maya version 1.50.SP1 from Dec 22 2010, 07:16:19
[2011/Jan/11|15:43:15] V-Ray: V-Ray core version is 2.00.01
Initializing V-Ray for Maya

File read in 5 seconds.
File read in 0 seconds.
Result: XXX/volumetrique.mb_RyYu59_vrayBatch.mb
Warning: Found camera ddm__v__066_903__p__camera__s__camera_maya__d__cam era:stereoCameraLeftShape.

V-Ray: Starting render
[2011/Jan/11|15:43:20] V-Ray: Loading plugins from "/usr/autodesk/maya2011-x64/vray/vrayplugins/libvray_*.so"
[2011/Jan/11|15:43:22] V-Ray: 100 plugin(s) loaded successfully
[2011/Jan/11|15:43:22] V-Ray: Finished loading plugins.
[2011/Jan/11|15:43:22] V-Ray: Exporting scene to V-Ray.
[2011/Jan/11|15:43:22] V-Ray: Parsing light links time 0h 0m 0.1s (0.1 s)
[2011/Jan/11|15:43:23] V-Ray: Translating scene geometry for V-Ray
[2011/Jan/11|15:43:23] V-Ray: (Estimated time remaining: 0h 0m 0.5s): 17 % completed
[2011/Jan/11|15:43:23] V-Ray: (Estimated time remaining: 0h 0m 0.5s): 24 % completed
[2011/Jan/11|15:43:23] V-Ray: (Estimated time remaining: 0h 0m 0.9s): 30 % completed
[2011/Jan/11|15:43:23] V-Ray: (Estimated time remaining: 0h 0m 1.3s): 40 % completed
[2011/Jan/11|15:43:24] V-Ray: Total time translating scene for V-Ray 0h 0m 1.4s (1.4 s)
[2011/Jan/11|15:43:24] V-Ray: Rendering.
[2011/Jan/11|15:43:24] V-Ray: Pre-render export.
[2011/Jan/11|15:43:24] V-Ray: Pre-render export
[2011/Jan/11|15:43:24] V-Ray: Pre-render export done.
[2011/Jan/11|15:43:24] V-Ray: Rendering frames.
[2011/Jan/11|15:43:24] V-Ray: Updating frame at time 1.00
[2011/Jan/11|15:43:24] V-Ray: (Estimated time remaining: 0h 0m 1.2s): 11 % completed
[2011/Jan/11|15:43:24] V-Ray: (Estimated time remaining: 0h 0m 0.8s): 23 % completed
[2011/Jan/11|15:43:24] V-Ray: (Estimated time remaining: 0h 0m 0.5s): 41 % completed
[2011/Jan/11|15:43:24] V-Ray: (Estimated time remaining: 0h 0m 0.2s): 67 % completed
[2011/Jan/11|15:43:24] V-Ray: (Estimated time remaining: 0h 0m 0.0s): 92 % completed
[2011/Jan/11|15:43:24] V-Ray: Total time updating frame 0h 0m 0.5s (0.5 s)
[2011/Jan/11|15:43:24] V-Ray: Preparing renderer...
[2011/Jan/11|15:43:24] V-Ray: Preparing scene for rendering...
[2011/Jan/11|15:43:24] V-Ray: Preparing scene for frame...
[2011/Jan/11|15:43:24] V-Ray: Compiling geometry...
[2011/Jan/11|15:43:24] V-Ray: Building static raycast accelerator...
[2011/Jan/11|15:43:24] V-Ray: SDTree statistics:
[2011/Jan/11|15:43:24] V-Ray: Total number of faces stored: 64327
[2011/Jan/11|15:43:24] V-Ray: Max tree depth: 33
[2011/Jan/11|15:43:24] V-Ray: Average tree depth: 17.4214
[2011/Jan/11|15:43:24] V-Ray: Number of tree nodes: 21727
[2011/Jan/11|15:43:24] V-Ray: Number of tree faces: 174701
[2011/Jan/11|15:43:24] V-Ray: Number of tree leafs: 8455
[2011/Jan/11|15:43:24] V-Ray: Average faces/leaf: 20.6624
[2011/Jan/11|15:43:24] V-Ray: Memory usage: 7.49 MB
[2011/Jan/11|15:43:24] V-Ray: Rendering image...
[2011/Jan/11|15:53:07] V-Ray: (Estimated time remaining: 1h 27m 25.2s): 10 % completed
[2011/Jan/11|15:59:16] V-Ray: (Estimated time remaining: 1h 2m 39.1s): 20 % completed
[2011/Jan/11|16:00:21] V-Ray: (Estimated time remaining: 0h 38m 6.0s): 30 % completed
[2011/Jan/11|16:07:18] V-Ray: (Estimated time remaining: 0h 35m 32.1s): 40 % completed
[2011/Jan/11|16:07:55] V-Ray: (Estimated time remaining: 0h 23m 55.9s): 50 % completed
[2011/Jan/11|16:17:17] V-Ray: (Estimated time remaining: 0h 22m 35.1s): 60 % completed
[2011/Jan/11|16:28:34] V-Ray: (Estimated time remaining: 0h 19m 21.0s): 70 % completed
[2011/Jan/11|16:31:34] V-Ray: (Estimated time remaining: 0h 12m 2.4s): 80 % completed
[2011/Jan/11|16:47:18] V-Ray: (Estimated time remaining: 0h 7m 5.9s): 90 % completed
[2011/Jan/11|17:03:22] V-Ray: Number of raycasts: 3560781222
[2011/Jan/11|17:03:22] V-Ray: Camera rays: 2953789081
[2011/Jan/11|17:03:22] V-Ray: Shadow rays: 606992141
[2011/Jan/11|17:03:22] V-Ray: GI rays: 0
[2011/Jan/11|17:03:22] V-Ray: Reflection rays: 0
[2011/Jan/11|17:03:22] V-Ray: Refraction rays: 0
[2011/Jan/11|17:03:22] V-Ray: Unshaded rays: 0
[2011/Jan/11|17:03:24] V-Ray: Successfully written image file "volumetrique_masterLayer_cam_066_903_0left_V5.000 1.exr"
[2011/Jan/11|17:03:24] V-Ray: Total frame time 1h 20m 0.3s (4800.3 s)
[2011/Jan/11|17:03:24] V-Ray: Total sequence time 1h 20m 0.3s (4800.3 s)
[2011/Jan/11|17:03:24] V-Ray: Render complete
[2011/Jan/11|17:03:24] V-Ray: ========================
[2011/Jan/11|17:03:24] V-Ray: Clearing exporter memory...
[2011/Jan/11|17:03:24] V-Ray: Total time clearing exporter memory 0h 0m 0.0s (0.0 s)

[vlado]

It would render a lot better if you put the lights right outside the windows and match their size. The way you have it set up now, only a very small percentage of the shadow rays actually reach the large lights through the small windows, leading to increased noise.

Best regards,
Vlado

[pgenin]

Hello,
Thanks for your response.
In fact, there are many windows , six (not visible on this frame), so i choosed to place only a larger one to cover the 3 windows on each side.
Moreover, if i put the light to fit the window. I can't have the raylight matching to my actual position. All the rays will be spread, (larger)...
So i understand clearly that put a light far away from my frame will cause noise with the envFog.
I 'm going to try with lights closer...
Another point is about the problem of rendering, on the frame you see black squares! It's not because i stop the rendering, it is the result of the rendering of the frame, it seems to be a bug?!
Have you got an idea about this problem? Do you need my scene?
Thanks

Pierre

[vlado]

For the black squares it might be because of the noise (if in the initial sampling phase V-Ray finds only black pixels, it will not sample any more). You can try increasing the min. samples for the image sampler.

Another solution could be to use the ray marching method for the fog instead of random sampling - to do this, just plug any texture into the color slot of VRayEnvironmentFog (could be just a solid color texture).

Best regards,
Vlado

[pgenin]

Hello,
I fix the problem of Black squares by increasing the min sample, thank you!.
I will test the raymarching later because of times. The rendering is really faster if i place lights close to the window and less noisy by the way.
no need to increase the subdivision of the EnvFog, 8 is a good value. (not 256...)
I did that with Spotlight to control the angle of raylights.
It works well now, thanks again.

Pierre