VRay Distributed Rendering Tip

[ericbarlow21]

Hello All -

 

I wanted to share a quick tip regarding VRay Distributed rendering. Here at work we needed to render an image over 2 computers (each with 8 processor threads) and found then when we would connect to the client pc to use it's processing power, we would only recieve 1 extra bucket in the rendering frame when we should've been recieving 8 more buckets (1 per processor thread).

 

We setup our distributed rendering as documented on spot3d.com by Chaosgroup but could not find a solution to our problem.

 

Anyways, the solution is simple and only requires you to enter a small script into 3DS Max.

 

After setting up the distributed rendering as documented, hit F11 to open the Maxscript window. As previously mentioned, we should've been utilizing a total of 16 processor threads thus giving us 16 buckets in the render frame.

 

After pressing F11, enter the following:

 

renderers.current.system_numThreads=X

 

("X" being a numerical value equaling the number of threads you are wanting to utilize for example: renderers.current.system_numThreads=8). Hit enter and close the script window and you are set to go!

 

We have also found through some experimenting that in the VRay rollout settings, the "Number of Passes" needs to equal the number of threads entered into the script or you will not recieve the correct amount of threads in the rendering frame.

 

If anyone has anything to add to this I would love to hear about it! I apologize if this is common knowledge - we are kinda noobs here so please forgive me if this is incorrect or already known.

 

Hope this helps someone!

[martin walker]

thanks Eric...very interesting

[Woody]

Cheers!!!

[MegaPixel]

So out of curiosity, are those 8 threads coming from a Dual QX6700 setup?

[ericbarlow21]

Yes MegaPixel - 2 Quad Cores

 

I hope this answers your question!

 

Although my original post would be true for any processor with more threads than one. Anytime you would need to take advantage of a clients multi-threads you would use the script and enter the highest number of threads for example from what we have found here if you have a client with one processor with 8 threads, another client with 4 threads, another client with 2 threads, you would still enter 8 threads.

 

I may be wrong on one thing though which I will test today and that is that with the previous example given, you may need to add 8 + 4 + 2 = 14 and use that sum as the numerical value in the script. I have only tried this on one other client so far so I am not sure on whether to use only the highest number of threads on one machine or to use the sum of all together but I am suspecting this to be true for using more than one client - all processor threads must be added and the total sum used in the script of ALL clients threads. I will test this and post again.

 

If anyone else has any info on this I would love to hear it!

 

Thanks!

[g1nchy]

Vray / Subst Drive Windows 7 and missing bitmaps.

I use a subst drive on all my machines to a local path 'J:'

I noticed the bitmaps missing on slave machines buckets.

The problem was with using a batch file to run the subst command.

The fix is to issue a subst command using regedit there is a helpful command on wikipedia see link

http://en.wikipedia.org/wiki/Subst#Persisting_across_reboots

Run Regedit

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices]

add a string, substitue X for a drive letter

"x:"=\\DosDevices\\C:\\Path