• You don't have to log in onto a desktop
this means that you can leave the computers free for use by other students.
• You don't even have to be in the robot lab
forgot to render that final animation? no problemo, just ssh in from your desktop in your dormroom and start it up. Along similar lines...
• You can schedule the rendering to take place during times that the computer won't find itself being used by other students.
the computers are often just sitting and idling for most of the late morning and early afternoon hours.
• You can (should) schedule the rendering to run at a lower priority
not only can you leave the computer free for other students to log in, but you can also lower the priority of your rendering so it won't get in the way (too much) of desktop activity for the other students.
And most importantly:
• You can farm out your rendering job
You can distribute the job to all of the computers in the robot lab, meaning you can cut your rendering time to up to 1/8th the time it would normally take. Sweet...

all you have to do is follow these simple steps

Simple command-line rendering

step 1: set up

For a quick simple example, you only need to make sure you have your scene set up correctly in maya, and then make one small change to your shell environment before you can begin:

In maya:

• in Render mode, select Window - > Rendering Editors - > Render Globals
• expand the section labeled Image File Output
• for the field Frame/Animation Ext, choose name.#.ext
• set up the rest of the rendering globals how you want them (i.e Image Format, Ray Tracing, et c.)
• that's it

step 2: add a directory to your path

• for bash users:
export PATH=${PATH}:/usr/aw/maya4.0/bin
• and for tcsh users:
setenv PATH "${PATH}:/usr/aw/maya4.0/bin"

you can either type those examples in every time you need them, or save yourself the keystrokes by putting them in your default rc files. for people who use bash, that's .bashrc. for people who use tcsh, that's .cshrc. If you don't know what shell you use, it's probably tcsh, so go ahead and try it with that. If it doesn't work, then you're probably using bash.

step 3: render

okay, now we're ready to render. Assuming you have a scene called Foo.mb, you can Render your scene like so:

Simple, no? Well now that you've done that, let's talk about more advanced uses of this ability

Advanced uses of command-line rendering

Using nohup

nohup is a simple shell command that tells the program it's told to run not to exit when you log out. It's great for leaving long running processes in the background without having to keep a shell open--i.e. keeping them running in case you need to or accidentally log out (or if the windows computer on which you've logged in freezes and needs to be restarted.)

Again, pretty simple. the '&' tells the shell to not only nohup the command, but to also run it in the background, letting you continue on with whatever else you want to do. It will probably say something like Sending output to nohup.out. By default, nohup spits all of its output (both stdout and stderr) into a file called nohup.out, which can be very useful for examining in case something doesn't work correctly with your job. nice tells the operating system to give the command a lower scheduling priority, which is very "nice" to other users of the computer (but won't make it slower if no on is using the computer)

Simple batch rendering

A simple example of batch rendering uses two of the commandline options to Render, see if you can follow:

the -f option to ssh tells ssh that you're not really wanting to log in to do any more than run the given command at each of the destinations (i.e. cream, oil, milk). If you are already using ssh-agent, this is the same as the -n option, and you won't be asked for your password.

Advanced command-line rendering

sleep, and other methods to defer rendering to a certain time

using the commands such as sleep,at, or by starting and editing a crontab file on one of the linux macchines, you can specify to start the rendering at a later point in time (like, if you've finished one project, but don't want to start rendering while you're working on the next project, or if you don't want to start rendering while other people are using the computer because you're a polite student).

using ssh-agent to make life easier

using ssh-agent and your own personal ssh private/public DSA key pair, you can ssh from machine to machine without having to enter a password. This is great for writing scripts to automatically farm out your rendering jobs, or for using the preceding sleep example.

next, copy your id_dsa.pub file to a file called /home/yourusername/.ssh/authorized_keys2.

next, put this in your /home/yourusername/.xsession, just before the line that calls your windowmanager:

the next time you login to your favorite machine, you'll be prompted by a little program that asks you for your passphrase. enter it, and then ssh happily and password-free for the rest of your session. (note: you can also enter those two commands on the command line, if you're logged in remotely)

Truly 1337 rendering

Alas, I am not 1337 enough to say I could tell you how to be a grand master and command line rendering. I have, however, ganked all of the command line options that you can pass to Render, and put them in a file, here.

(happy rendering)