Command Line Manual Cook Mode

Start Houdini in “Manual” Cook Mode

Here is a tip to end the week that is not very glamorous but I’m sure one day will come in handy, so keep it tucked away in your small jeans pocket for future use. It involves using the command line to start Houdini in manual cook mode to open up a problem file.

Cooking Your Goose

So I’ve been implementing chaotic attractors using Python SOPS but decided to try the Holversen Attractor in VEX. I got so caught up trying to get the code right that I forgot to actually save the working file. Yeah, yeah, whatever… Anyways, as it so happens when you are tweaking code or parameters, I ended up with a piece of code Houdini did not like very much. Houdini got stuck trying to “cook” the custom VEX SOP and I eventually had to force quit. Luckily, Houdini like a good citizen, cleaned up after itself and saved out the file in the tmp directory.

The problem was that attempting to reopen the file caused Houdini to start cooking that same operator and we were back at square one. What to do?

Command Line Options

If you are an After Effects user, you probably know that old trick of hitting CAPS LOCK before starting up an .aep file that is acting funky. Basically, the CAPS prevents After Effects from updating so it gives you a chance to go in and turn off any plugins, layers, etc that may be causing the issue. Well, if only you could do that in Houdini…

Well, you can but it does not involve CAPS LOCK. You need to start Houdini from the command line and throw in a command line option. Now, for those new to Houdini, “cooking refers to evaluating the nodes in the networks to compute the state of the scene in the current frame. Whenever you wire in a new node or change a parameter, Houdini re-evaluates the networks to compute the new outputs.”1 Throw that word around at the prom. You will be the star of the party.

This is really easy. All you do is type in houdini and pass the -n option followed by the file you want to open. The option -n tells Houdini to start in manual cook mode.

houdini [options] [file...]

You just open up a console or Terminal window and type in the following as an example:

houdini -n attc.hipnc
Command Line Manual Cook Mode
Command Line Manual Cook Mode

Done! Afterwards I was able to go in and change out the bad code and everything was back to normal.

There are several other options besides -n you can use such as specifying the number of thread Houdini uses. For more information on using the command line with Houdini, check out the documentation.




I am a motion designer & developer based out of South Florida. When not designing or animating pixels, I wrangle some code. If all else fails, I watch Twilight Zone, I Love Lucy, or Three's Company reruns.