element creation challenge makes automation trivial. Many studios that use Houdini on large feature effects, and feature animation projects develop libraries of procedures that can be used to automate generation of many of the elements for that film with almost no artist interaction. Also unique to Houdini is the range of I/O OPs available to animators, including MIDI devices, raw files or TCP connections, audio devices (including built-in phoneme and pitch detection), mouse cursor position, and so on. Of particular note is Houdini's ability to work with audio, including sound and music synthesis and spatial 3D sound processing tools. These operators exist in the context called "CHOPs" for which Side Effects won a Technical Achievement Academy Award in 2002. VEX (Vector Expression) is one of Houdini's internal languages. It is similar to the Renderman Shading Language. Using VEX a user can develop custom SOPs, POPs, shaders, etc. The current implementation of VEX utilizes SIMD-style processing. Rendering Houdini is bundled with a production-class renderer, Mantra, which had many similarities to RenderMan in its scope and application in its initial incarnation. Micropolygon rendering is supported, allowing high-quality displacement operations as well as traditional scan-line and raytracing modes. Shaders are scriptable and composed in their VEX language, or by using VOPs; their node-based interface to programming VEX. Mantra (as does Houdini itself) also supports point-clouds, which can be similar in application as brickmaps in Renderman. This allows more complicated light interactions, such as sub-surface scattering and ambient occlusion, to be produced with lower computational overhead. Mantra can perform extremely fast volume rendering, and also physically based path-tracing – a technique which attempts to more accurately model the physical interactions of light and materials. TouchDesigner Derivative Inc. is a spin-off of Side Effects Software that markets a derivative of Houdini called TouchDesigner. Tailored toward real-time OpenGL-generated animation, it was used on rock group Rush's 30th-anniversary tour to produce dynamic graphics driven directly by the musicians. TouchDesigner was also used by Xite Labs (formerly V Squared Labs) to create live visuals for Amon Tobin's ISAM installation tour. Production The notable works in which Houdini was used include the 1997 Contact movie and more recent 2016 Zootopia. See also References External links SideFX Software, Makers of Houdini 3D graphics software IRIX software 1996 software 3D animation software 3D computer graphics software for Linux Proprietary commercial software for Linux Motion graphics software for Linux