“Beam Fractals” provided by Cullen Hassel

Is MOPs really free?

Yes. MOPs is free and open source (LGPL). Even if commercial versions are released later, the current core toolkit will stay open source. Don’t worry.

Does MOPs work with [operating system] [Houdini version] [Houdini license]?

MOPs is entirely Houdini SOPs, VEX, and Python. It will work with any operating system or Houdini license. The minimum Houdini version to run MOPs is 16.5, but you should consider using Houdini 17.0.489 at a minimum, to be able to preview Falloff in the viewport.

Are MOPs a special kind of object in Houdini? Is MOPs a closed ecosystem?

No. MOPs operate on Houdini native packed primitives and geometry. With few exceptions, MOPs nodes will work on anything represented as points, whether they’re packed primitives, particles, or polygons. In most cases all you’d really need for stability is an “id” attribute on your points. You can mix and match MOPs nodes anywhere inside your SOP networks.

Will MOPs teach me how to use Houdini?

Not if you’re a total beginner, but it will make transforming things much less painful. MOPs still largely relies on basic Houdini workflows like attributes and groups. As long as you’re comfortable manipulating those, you should be fine with MOPs.

If you’re an intermediate or advanced user (nerd), you can of course open up the HDAs and peek around. You could learn something new, or even better, find a better solution and submit a pull request on Github!

How do I install MOPs? Do I have to edit some ENV file…?

Check the README on Github for the most up-to-date installation instructions. If you’re using Houdini 17.5+, installation using the “packages” method couldn’t be easier… you don’t need to edit the environment at all.

How can I contribute?

Aren’t you generous! There’s a few ways you can help out MOPs:


We have some outdated video tutorials available on Vimeo, but these take a long time to update. The best way to learn is to take a look at the MOPs Wiki, and look at the /examples/ HIP files that are included in the download. Or just ask in the forums!

Header image provided by Maxime Hacquard.