Like a certain famous escape artist, the software Houdini has created some of the most amazing “illusions of reality” of our time. From “Guardians of the Galaxy Vol. 2”, to “Star Wars: The Last Jedi” to TV’s “Game of Thrones” and Netflix “Stranger Things” you have surely encountered some of Houdini’s magic. Appropriately named I would say!

Houdini is a fully procedural 3D Animation package developed by SideFX, based in Toronto. SideFX adapted Houdini from their PRISMS suite of procedural animation software tools. Houdini was first released in 1996, and since then has become the leading software for the VFX industry creating some of the top Academy Award effects you see in almost every movie today. From Animation to VFX, Gamedev and Motion Graphics, VR and more Houdini is laying the groundwork to becoming the go-to software in all aspects of the entertainment industry.

What makes Houdini so powerful? Houdini has a node-based workflow that is different than your traditional 3D tools, and this is what sets this tremendously powerful software apart. Over the last few years it has gained significant traction in the Animation and VFX industry to the point that some studios have changed most of their pipeline over to use Houdini. Artists are being trained in house to keep up with their studios needs.

Eric D. Légaré, Senior Creature TD (Weta, ILM, Digital Domain, Ubisoft…) quotes: “Houdini is quickly becoming the standard for CFX, so learning how to work in Houdini is a must these days.”

Me: “Was the transition difficult for you and did it improve your overall work? Is the workflow easier?”

Eric: “Houdini is like being in a different world, it took some time to adapt my thinking.

By making things in a procedural way I can reuse setups much more easily, like a muscle/fascial/fat/skin setup that would take a month to setup on each character, with Houdini that workflow is down to one day to adapt an existing setup to a new character.”

Me: “Wow! That’s pretty huge change of workflow then! That has also got to save your company a ton of money as well.”

Eric: “Definitely! I am never going back to doing CFX in Maya!”

Me: “How long did you say you were in the industry before using Houdini? And how long do you think it took to make that switch over?”

Eric: “Fourteen years in the industry doing VFX – it took me a good year to wrap my head around Houdini but it was worth the investment! The results look better because Houdini is more flexible so it’s easier to adapt.”

Me: “I’m going to assume this is going to make you much more valuable in the industry. Have you crossed over into other areas such as game?”

Eric: “My career started in games, but yes definitely! I know that places like EA are experimenting with Houdini as well.”

Eric D. Légaré has been working as a Creature TD since 2006 at several studios such as Weta, ILM, Digital Domain and Ubisoft. He has worked on titles including Avatar, The Hobbit: The Battle of the Five Armies, Game of Thrones and Star Wars: The Force Awakens.

What is Houdini and how is it used?

Houdini has features that cover different parts of the pipeline but its strengths lie in procedural modeling, dynamics and simulation. These are the areas of Houdini traditionally used by artists and studios to create environments and levels for video games, blockbuster VFX for movies and TV and cool looking motion FX for commercials.

But Houdini also covers other parts of the CG pipeline including lookdev and lighting, rendering, animation, and character FX such as hair, cloth and muscles. Improvements to the user experience in Houdini has made it more feasible for artists to turn to Houdini for a wider range of the production pipeline and coupled with Houdini’s procedural backbone, this is proving to be a powerful one-two punch.

Houdini’s networks of nodes come in different flavours such as SOPs for surface operators which process geometry, DOPs for dynamic operators, VOPs for shaders and visual scripting, CHOPs for motion, COPs for compositing and ROPs for output nodes. In fact these terms make up the unique language that Houdini artists use to communicate with each other. While this can make other artists feel out of the loop, there is no reason to be intimidated since Houdini is very accessible with lots of tutorials available on the SideFX website. And more and more schools are teaching this important software to ensure that their students are job-ready when they apply to top studios.

Robert Magee, SideFX discussing Houdini’s workflow

Houdini is also an open environment and supports scripting APIs such as Python which is used by most industry professionals and is intended to compliment its own scripting languages such as Hscript and VEX. What makes Houdini powerful is its adaptability, and scripting languages which support socket communication can interface with Houdini as well.

Another exciting technology is Houdini Engine which makes it possible to take procedural assets from Houdini and open them in host applications such as Autodesk Maya, 3DS Max, or Cinema 4D, or into game editors such as Unity or Unreal Engine. The assets load into the host application with all of the procedural controls available. When an artist manipulates the asset, Houdini Engine works under the hood to recook the results and deliver them to the viewport. This gives artists the power of Houdini’s procedural architecture right inside their favorite app.

This is especially useful in game editors where level designers can quickly populate an environment using high level tools created as digital assets. Ubisoft took advantage of this technique in Far Cry 5 and has been using Houdini for a number of years to keep up with the growing demand for larger worlds with more and more content. SideFX has a team of TD’s working on Gamedev tools which solve a range of specific day-to-day issues and these tools have even proven beneficial to artists working in film and TV. VR developers have also turned to Houdini to create immersive experiences.

Ubisoft talks about Houdini in Far Cry 5

Recent Innovations

Introduced in Houdini 17, VELLUM is a fast, unified solver for creating cloth, hair, soft bodies and grains. You can also integrate all of these VELLUM effects within a single simulation. The cloth solver is accelerated using OpenCL, and supports multi-layered, paneled and draped cloth and dynamic constraints for stitching, branching and tearing.

Houdini 17.5 also introduced the Procedural Dependency Graph (PDG), which is designed to take Houdini’s procedural architecture to the compute farm. This new context in Houdini is called TOPS or Task Operators and you can use it to distribute tasks and manage dependencies to better scale, automate, and analyze content pipelines.

PDG can be used to automate the creation of artwork for film and games and can use wedging to create design variations to help make creative decisions. This graph can also run scripts and access other applications through their scripting UIs. It also offers a great tool for building datasets for use in Machine Learning to train systems.

What awards has SideFX received?

SideFX has been recognized by the Academy of Motion Pictures, Arts and Sciences four times for Houdini and its procedural based technology – in 1997, 2002, 2011 and in 2018, where SideFX received the prestigious Academy Award of Merit (the Oscar). In 2019, SideFX has also been awarded a Technology & Engineering Emmy Award in the “Cost Effective Crowd Simulation Tools” category.

How can you become a Houdini master?

To assist with learning, SideFX offers a free Houdini Apprentice editions where the only limitations are a maximum render size of 1280×720, a render watermark and no commercial work allowed. Within Houdini you can create physically based effects like fire, smoke, water, fluids, explosions, destruction without relying on 3rd party plug-ins.

There is also an Indie version for use by indie game devs and filmmakers who are just getting started in the industry and are bringing in less than $100K USD. This version has some render size limits (4K) but no watermark and includes the ability to create digital assets that can be loaded up into other applications using free Houdini Engine Indie licenses.

Everything in Houdini is supported by the node based approach and it works on OSX, Windows and LINUX. Houdini comes with a great in built renderer Mantra, which is similar to Renderman. Mantra’s quality is superb to the effect that you don’t need a 3rd party renderer, you can get top end beautiful renders right out of the box. But the commercial and indie versions of Houdini supports 3rd party rendering engines such as: Renderman, Redshift, V-ray, Octane, and Arnold.

The Future

What does the future hold for the team at SideFX. While releasing Houdini 17.5, SideFX teased lookdev and lighting as the next key area of focus. With USD (Universal Scene Description) quickly becoming a standard in studios around the world, the new tools in Houdini will bring yet to be seen advancements to lighting workflows. There are also studios working with their animation and rigging tools to help SideFX explore even more of the pipeline. And with PDG and Machine Learning, we may soon see Houdini technology being used by people outside the traditional content creation space.

While VFX remain the area where Houdini truly shines, recent developments in gamedev, user experience, character FX and more show that more and more CG artists will be using Houdini in the future. And while it still has a reputation for being a challenging software to learn, artists are quickly learning that it is a challenge that is worth the effort.

**Special Thank you to Eric D Légaré, Creature TD for the interview and for the technical content thank you to SideFX, Robert Magee and for the connection to help get this article created a special shout out to Ari Danesh and Christopher Hebert from SideFX as well.

**Links pulled from SideFX website 2019

If you have any questions or feedback on this blog, we’d love to hear it in the comment section below or email me at lori@cgcircuit.com

About the Author:

Lori Hammond, CG Circuit