MOPs Plus

MOPs Plus Ident from Toadstorm Inc on Vimeo. I’ve finally released MOPs Plus, the commercial add-on to the MOPs toolkit for Houdini. It adds some fancy new toys for typography, modifying packed primitives, greebling, randomizing textures and other string attributes, and more. It also extends MOPs into DOPs so you Read more…


MOPs @ Houdini Hive Worldwide

In case you haven’t seen it already, my presentation on MOPs at Houdini Hive Worldwide has been online for about a month now. Here’s the presentation: I’d forgotten to upload the example files I built during the presentation. They’ll be included in the examples directory in the next Experimental release Read more…


Doing away with Houdini.env

This is a sort of sequel to the previous post I made about handling the Houdini.env file, and about configuring environments in general. Houdini 17.5 introduced the concept of “packages”, which are little JSON files (JSON meaning JavaScript Object Notation, filling a similar role as XML or YAML) that define Read more…


Dealing with houdini.env

I continually run into confusion from Houdini users about how the Houdini.env is supposed to work, what the syntax is supposed to be, or even what it does in the first place. It’s easy if you’ve been trapped in pipeline land (like me) to think that environment configuration is even Read more…


Raytracing AOVs in Mantra

I meant to write a post about this a long while ago, but couldn’t be arsed to do it, apparently. Sorry! Something that artists take for granted in render engines like VRay and Arnold is the ability to reflect and refract AOVs / render elements / render passes, depending on Read more…


VEXpressions in your HDAs, using Python!

Update: Imre Tuske from Weta pointed out that there’s a simpler method… it turns out that you can force expressions to evaluate inside a Wrangle by wrapping them up in backticks. So if you have a channel called “do_vexpressions” to enable or disable VEXpressions, and another channel called “vexpression” that Read more…


The rainy forest cinemagraph, Part 2

Continued from the previous post.

Part 2 here is all about the hero plant, which was by far the most time-consuming part of this whole process. The animation ended up being done primarily using FEM, which in retrospect was probably overkill. If I were to try this again, I’d probably try to build a more procedural system involving IK chains with maybe a layer of simple soft body dynamics on top to add springiness. Going the FEM route meant that each iteration took about 30 minutes to simulate, which adds up pretty fast. There are some neat little shortcuts elsewhere in the process, though, that hopefully some readers will find useful.

The hero plant

I am a masochist so I again started with L-systems to create the basic plant structure. L-systems are one of those things that start very simple and quickly build in complexity until they’re totally unreadable, so you generally want to keep notes of what the rules are actually doing as you build them. Of course, the notes from the original .HIP file that I posted are outdated, as they apply to an older version of the plant, so if you’ve already checked out the .HIP you may want to read these more accurate notes.

Here’s what the rules look like: