Batch Rendering

Multithreaded Rendering

Mantra is a multithreaded process, which means that a single mantra render will split work between available processors to speed up rendering. By default, mantra detects the number of processors installed in the system and will start enough threads to use all of the processors.

You can turn off multithreaded rendering by unchecking the Use Max Processors checkbox on the Rendering sub-tab of the Properties tab on the mantra render node. You can also manually set the number of threads to use for rendering by setting the Thread Count.

Network Rendering

Network rendering makes it possible to split a single render among many rendering servers on a network.

Note	If you are rendering on a single system, multithreading usually outperforms network rendering. Therefore, network rendering is most useful when you want to distribute a render among many remote hosts.

Network rendering can only be used to distribute rendering tiles within a single image. If you want to distribute frames in an animation, you must use a render queue manager such as Alfred.

To enable network rendering, you must adjust the Command parameter on the Main tab of the mantra output driver.

For example:

mantra -H localhost,clinton,beijing,finland

This command line will start up mantra on 4 servers named localhost, clinton, beijing, and finland, and will send tiles back to the host once they are completed.

It is also possible to run more than one mantra process on a host.

mantra -j1 -H clinton,clinton,clinton

This command line starts up 3 mantra servers all on clinton.

If you are running more than one mantra server on a host, you must disable multithreaded rendering to ensure that processor resources are not exhausted. The -j1 option instructs mantra to only use single a single rendering thread.

Network Render Troubleshooting

Why is my render hung without any tiles being rendered?

Network rendering uses the hserver program to communicate with remote rendering servers and to start remote mantra processes. The most common technical issues that arise when using network rendering are either that the rendering server’s version of hserver does not match the version running on the host, or that there is not even an hserver process running on some of the servers. The most common symptom of this problem will be network renders that hang without completing any tiles.

You can check the version of hserver that is running on a render server by running the command hserver -l:

    !hserver -l
Hostname:       clinton [Linux (little endian)]
Uptime:         21:29:16        [Started: Wed Aug 15 18:11:48 2007]
License Server: internal
Server Version: sesinetd9.0.634
Version:        Houdini9.0.688
ReadAccess:     +.+.+.*
WriteAccess:    +.+.+.*

    4692 of 7983 Mb available
    CPU Usage: 3% load
    0 active tasks (4 slots)

The most important line in this example log is the hserver version Version: Houdini9.0.688. You should verify that the 9.0 portion of the version number listed for each render server matches the version of Houdini running on the host.

Linux

If the hserver version does not match, you need to restart the hserver. You can do this by stopping and restarting the hserver within the new Houdini environment.

hserver -q
cd /opt/hfs9.0.688
source houdini_setup
hserver

Windows

Windows will automatically use the latest version of mantra that is installed. However, this can introduce problems with network rendering when it is necessary to render using an older installed version of mantra. To do this, you must add an entry to the c:/windows/system32/hserver.ini file. See comments in hserver.ini for how to set this up.

mantra version=8.2 command="mantra8.2"