hi,
if i render my file locally with single frame i have a rendertime of 30 minutes (raw rendertime). if i do the same rendering in backburner with animation-prepass/animation-rendering i have a rendertime of 13 hours for the same frame on my computer.it begins to render very fast, but is freaky slow…
it´s a sidebyside stereopanoramafilm with 4000x1000 pixels.much of proxies, one small xref scene. same result.max2016 -vray3-20-01
no idea
please if any admin could delete the double post… it happened because i cannot edit my posts, the textfield is always empty… so i went back 
and posted again…sorry
We will need some way to reproduce the issue. Do you think you can provide a scene?
Best regards,
Vlado
I had this issue a year or two ago. I never got round to sending chaosgroup the file because I was too busy. Hopefully you can get it resolved!
the problem seems nothing really new…
600mb zipped on your server, vlado got mail
I´m pretty sure you would be better off with brute force+light cache.
As Vlado explained before. IR+LC is a interpolated method, that deson´t work that well with lots of details. I had some success reducing the number of interpolation frames for the animation rendering part (after you recorded the prepass), but in the end I had much better results with BF+LC and some more scene optimization (Up the light samples alot, especially if working with dome lights, also make sure BF samples are high enough, you might even consider slightly increasing the color noise threshold from 0.1 to 0.15 or even 0.02, depending on your scene).
Here are the results from our tests on the scene(maxfile.max) you sent us:
The tests have been executed on a smaller resolution 1000x250 instead 4000x1000.
We have used the Irradiance Map cache file(stereo_licht_.vrmap) which comes with the scene.
3DSmax/BB and V-Ray versions were 2016/2016 and 3.20.02.
Local render and BB render(on the same machine) took the same amount of time on the original scene(1000x250).
Please note that 3DSMax measures differently the local rendering times and BB times. When the scene is rendered locally the time for opening 3DSmax and scene loading is not included in the final render time since these operations have been already done but when rendering with BB the final render times include those components.
After applying default V-Ray material to all objects we have measured the times for rendering and loading precisely.
When rendering the scene locally launching 3DSmax and loading the scene took about 5:03 and then the actual rendering took about 1:17 so the final render time was 6:21.
When rendering via BB the time for launching 3DSMax and loading the scene took about 4:50 and the actual rendering took about 1:20 resulting 6:10 as a total render time.
Would it be possible to repeat the same tests into your environment with the same 3DSMax/BB/Vray version that we have used here and with the simplified version of the scene?
I am going to send you that version to your email in a few minutes.
Looking forward to hearing from you.
again the problem with irrmap/BF “animation prepass” rendering in backburner…job starts with 1 minutes and with every calculation the rendertime goes higher up to one hour…if you suspend the job and activate it again, the rendertime begins again at 1 minute and starts rising.
rendering itself goes fine and with stable time !
Any chance to send us that scene over.
Maybe this time we will be able to reproduce the issue?
What are the versions of V-Ray/3dsMax and BB that you are using.
thanks svetlozar,
too difficult, veeery big matte file with anima people. all i know is that the ram did not! rise from frame to frame…that was, as i know controlled. when restarting the renderjob the calculation time started small again.
thomes
after looking into the tutorials 
we maybe found the problem.
with interpolation frames set to 2 the interpolation samples with “50” were much too high. we set the interpolation samples to 5 and the render times got ok. with many objects in the scene that have got very much small faces like bushes, the intrepolated calculation rendering time for these objects explode.
in other scenes without these “problematic objects” the render times were pretty ok.
…
2.2.2. Set the Interp. samples to 5. It controls the number of GI samples from each irradiance map that will be used to interpolate the indirect illumination at a given point. Since we are using several irradiance maps for the rendering, we can decrease that parameter depending on the settings for the Interp. frames.