Houdini 21.0

Houdini third-party libraries and tools

Houdini 21.0 is compliant with the VFX Reference Platform CY2025 specification (http://www.vfxplatform.com).

Houdini variant builds are available to help studios transition between VFX Platform specifications. There are Houdini Qt 5 builds for all platforms. Aside from the deviating Qt version, the variant builds remain compliant with the rest of the VFX Reference Platform CY2025 specification.

Houdini uses the following third party libraries:

Third-Party Tool Version License VFX Platform Compliant
aiohttp 3.8.4 Apache 2.0 License N/A
aiosignal 1.3.1 Apache 2.0 License N/A
Alembic

1.8.3

Uses version namespace with sidefx suffix 		License Yes
Apache Thrift 0.13.0 Apache 2.0 License N/A
asn1crypto 0.24.0 MIT License N/A
async-timeout 4.0.2 Apache 2.0 License N/A
attrs 22.2.0 MIT License N/A
Autodesk FBX (closed source)

2020.0.1

The Apple Silicon builds use FBX SDK 2020.2 which is required for M1 support 		License Yes
bcrypt 3.1.7 Apache License, Version 2 N/A
Berkeley DB 4.5.20 License N/A
Blosc 1.20.1 License N/A
Boost

1.85.0

Uses custom hboost namespace 		Boost Software License

Yes

The Boost libraries are renamed with symbols namespaced
Bullet 3.25 License N/A
bzip2 1.0.5 BSD-style License N/A
cereal 1.3.2 BSD 3-Clause License N/A
certifi 2025.7.14 Mozilla Public License 2.0 N/A
cffi 1.12.3 MIT License N/A
cgltf 1.14 MIT License N/A
chardet 3.0.4 LGPL 2.1 License N/A
charset-normalizer 3.0.1 MIT License N/A
COLLADA DOM 1.4.1 SCEA Shared Source License N/A
ColorAide 3.1.2 MIT License N/A
cryptography 2.7 BSD License or Apache License, Version 2.0 N/A
cssutils 2.3.1 LGPL 3 License N/A
CUDA 12.8 NVIDIA Software License Agreement N/A
cuDNN 9.7.0.66 NVIDIA Software License Agreement N/A
cURL 8.9.1 License N/A
dav1d 1.5.1 BSD 2-Clause License N/A
decNumber License N/A
Dem Bones 1.2.1 BSD 3-Clause License N/A
demjson 2.2.4 LGPL 3 License N/A
DirectXTex 2020.09.30 MIT License N/A
ecdsa 0.13 MIT License N/A
Eigen 3.4.0 MPL 2.0 License, LGPL 2.1 License N/A
Embree

3.13.1

Uses namespace with sidefx suffix 		Apache 2.0 license N/A
Expat 2.0 MIT License N/A
FFmpeg 7.1.0 LGPL 2.1 License N/A
Flicks

1.0

 BSD License N/A
Fontconfig 2.8 License N/A
FreeType 2.9 FreeType License N/A
frozenlist 1.3.3 Apache 2.0 License N/A
future 0.18.2 MIT License N/A
Genshi 0.7.7 License N/A
Geogram (MultiPrecision component only) 1.3.7 License N/A
gettext 0.14.5 LGPL 2 License N/A
glslang 11.13.0 License N/A
HDF5 1.8.11 License N/A
hiredis 1.0.2 License N/A
html5lib 1.1 License N/A
idna 2.6 BSD-like N/A
imageio 2.6.1 BSD-2-Clause License N/A
Imath

3.1.5

Uses internal namespace with sidefx suffix 		BSD 3-Clause “new” or “Revised” License

Yes

The Imath libraries are renamed with symbols namespaced
Intel(R) Math Kernel Library 2025.1 Intel Simplified Software License

Yes

oneMKL is used on Linux and Windows while macOS continues to use MKL. The MKL and oneMKL libraries are statically linked into Houdini and have their symbols hidden
Intel(R) Threading Building Blocks 2022.1.0 Apache 2.0 License Yes
ICU 5.1 License N/A
jemalloc 3.6.0 License N/A
Jinja2 3.1.2 BSD 3-Clause License N/A
Khronos OpenCL ICD 1.2 License N/A
KissFFT License N/A
kvazaar 2.3.1 License N/A
LAME 3.100 LGPL 2 License N/A
LASzip 3.5.0 License N/A
libarchive 3.7.2 New BSD License N/A
libdwelf 2.0.0 BSD 2-Clause License N/A
libe57 1.1.312 License N/A
libevent 2.1.12 BSD 3-Clause License N/A
libigl 0.1 MPL 2.0 License N/A
libiconv 1.14 LGPL License N/A
libjpeg-turbo 3.0.1 License N/A
libpng 1.6.36 License N/A
libspnav 0.2.3 BSD License N/A
libtiff 4.7.0 License N/A
libvpx 1.15.0 MIT License N/A
v4l-utils (libv4l only) 1.28.1 LGPL 2.1 License N/A
libxml2 2.9.7 License N/A
llvm 4.0 License N/A
Linearly Transformed Cosines reference implementation License N/A
Linearly Transformed Cosines reference implementation License N/A
lz4 3.1.0 BSD 2-Clause License N/A
lz4 Bindings for Python 3.1.0 BSD 3-Clause License N/A
lxml 5.0.1 BSD License N/A
Mako 1.2.4 MIT License N/A
MaterialX 1.39.3 Modified Apache 2.0 License N/A
materialyoucolor-python 2.0.10 MIT License N/A
mbedtls 3.2.1 Apache 2.0 License N/A
MikkT 1.0 License N/A
MoltenVK 1.2.11 Apache 2.0 license N/A
multidict 6.0.4 Apache 2.0 License N/A
MurmurHash3 1.0 Public Domain license N/A
MySQL Connector/C++ 8.0.30 GPLv2 N/A
nanobench 4.3.11 MIT License N/A
nanobind 2.0.0 BSD 3-Clause License N/A
NanoVDB 32.6.0 Mozilla Public License 2.0 Yes
nose 1.3.7 LGPL 2.1 License N/A
nng 1.1 MIT License N/A
NumPy 1.26.4 License Yes
ONNX Runtime 1.20.1 MIT License N/A
Open Shading Language

1.13.12.0

Uses namespace with HOSL prefix 		License N/A
OpenColorIO

2.4.1

Uses custom sidefx namespace 		License

Yes

The OpenColorIO libraries are renamed with symbols namespaced
Intel OpenCL CPU Driver

intel

Version 1.2-6.4.0.37-3 is used for Windows and the Linux gcc 9 build. 		License N/A
OpenCV

4.7.0

Uses namespace with sidefx suffix 		Apache 2.0 License N/A
OpenEXR

3.3.2

Uses internal namespace with sidefx suffix 		License

Yes

The OpenEXR libraries are renamed with symbols namespaced
OpenFX 1.4 BSD 3-Clause License N/A
openh264 2.6.0 BSD 2-Clause License N/A
OpenImageDenoise 2.2.1 Apache 2.0 License Yes
OpenImageIO

2.5.18.0

Uses custom HOIIO namespace 		Modified BSD License N/A
openpgl

0.5.0

Uses namespace with sidefx suffix 		Apache 2.0 license N/A
openldap 2.6.8 OpenLDAP Public License N/A
OpenSSL 1.1.1 License N/A
OpenSubdiv 3.6.0 Apache 2.0 License Yes
OpenVDB

12.0.1

Uses version namespace with sesi suffix 		Mozilla Public License 2.0 Yes
OptiX 9.0.0 License N/A
p4python 2023.1.2477632 Freely Distributable License N/A
paramiko 2.6.0 LGPL 2.1 License N/A
ply 3.11 BSD License N/A
psutil 5.8.0 BSD 3-Clause License N/A
Ptex 2.4.1 License Yes
pybind11 2.11.1 BSD License N/A
pycryptodome 3.20.0 Public Domain and BSD 2-Clause license N/A
pycurl 7.45.2 License N/A
Pillow 9.0.1 PIL Software License N/A
plumbum 1.6.7 MIT License N/A
pycparser 2.12 License N/A
pynacl 1.3.0 Apache License, Version 2.0 N/A
pyparsing 2.4.7 MIT License N/A
pyobjc 10.1 MIT License N/A
Python 3.11.7 Python Software Foundation License Yes
PySide6 6.5.3 LGPL 2 License Yes
Qt 6.5.3 LGPL 2.1 License Yes
Qt.py 1.2.3 MIT License N/A
requests 2.31.0 Apache 2.0 License N/A
rpyc 4.1.0 MIT License N/A
simplejson 3.16.0 MIT License N/A
SimpleJSON C# MIT License N/A
sse2neon MIT License N/A
SDL2 2.0.5 License N/A
SVT-AV1 3.0.0 BSD 3-Clause Clear License N/A
XSLT 1.1.32 MIT License N/A
Spectra 1.0.1 MPL 2.0 License N/A
SPIRV-Cross 1.3.236 Apache 2.0 License N/A
SPIR-V Headers 1.3.236 License N/A
SPIR-V Tools v2022.4 Apache 2.0 License N/A
SQLite 3.44.2 Public Domain license N/A
SwiftShader Apache 2.0 License N/A
Tcl/Tk 8.6.10 Tcl/Tk Licensing Terms N/A
tinybvh 1.4.9 MIT License N/A
Tracy 0.11.1 3-clause BSD N/A
urllib3 2.0.4 MIT License N/A
USD 25.05 Modified Apache 2.0 License N/A
USD File Format Plugins by Adobe 1.0.7 Apache 2.0 License N/A
Vicon Datastream SDK 1.11 MIT License N/A
volk 1.3.296 MIT License N/A
Vulkan Loader 1.3.236 License N/A
Vulkan Memory Allocator 3.0.1 MIT License N/A
Vulkan Validation Layer 1.3.236 Apache 2.0 License N/A
Qualisys CPP SDK 1.24 MIT License N/A
xerces 3.1.4 Apache 2.0 License N/A
xxHash 0.8.1 BSD 2-Clause License N/A
XZ Utils 5.2.3 Public Domain license N/A
yaml-cpp 0.6.3 MIT License N/A
yarl 1.8.2 Apache 2.0 License N/A
zlib-ng 2.1.6 zlib License N/A
zstd 1.5.7 BSD 3-Clause License N/A
3DxWare 3.3.1 3Dconnexion License N/A

Houdini’s help system additionally uses the following third party libraries:

Third-Party Tool Version License VFX Platform Compliant
blinker 1.6.2 MIT License N/A
click 8.1.6 BSD 3-Clause License N/A
Colorama 0.4.6 BSD 3-Clause License N/A
contourpy 1.3.1 BSD 3-Clause License N/A
cycler 0.12.1 BSD License N/A
Flask 2.3.2 BSD 3-Clause License N/A
fonttools 4.55.4 MIT License N/A
furl 2.1.0 Freely Distributable, Unlicense N/A
importlib-metadata 6.8.0 Apache 2.0 License N/A
itsdangerous 2.1.2 BSD 3-Clause License N/A
kiwisolver 1.4.8 BSD License N/A
libsass 0.19.2 MIT license N/A
MarkupSafe 2.1.3 BSD 3-Clause License N/A
matplotlib 3.10.0 Python Software Foundation License N/A
orderedmultidict 1.0.1 Freely Distributable, Unlicense N/A
packaging 24.2 Apache Software License, BSD License N/A
Pygments 2.4.2 BSD License N/A
PyOpenGL 3.1.1a1 License N/A
python-dateutil 2.9.0.post0 Apache Software License, BSD License N/A
webencodings 0.5.1 BSD License N/A
Werkzeug 2.3.6 BSD 3-Clause License N/A
Whoosh 3.0.0 BSD 2-clause License N/A

HQueue additionally uses the following third party libraries:

Third-Party Tool Version License VFX Platform Compliant
AngularJS 1.5.8 MIT License N/A
asgiref 3.3.1 BSD License N/A
coverage 5.5 Apache 2.0 License N/A
Django 3.1.5 BSD 3-Clause “New” or “Revised” License N/A
jQuery 3.6.0 MIT License N/A
pytz 2020.1 MIT License N/A
setuptools 65.5.1 MIT License N/A
six 1.16.0 License N/A
sqlparse 0.4.1 BSD-3-Clause License N/A
waitress 2.0.0 ZPL 2.1 N/A

SideFX Labs additionally uses the following third party libraries:

Third-Party Tool Version License VFX Platform Compliant
Dem Bones master BSD 3-Clause License N/A
GoZ (closed source) N/A
Instant Meshes master BSD 3-Clause License N/A
mercantile 1.2.1 BSD 3-Clause “New” or “Revised” License N/A
Substance by Adobe (closed source) N/A

Houdini Build Configuration:

Third-Party Tool Version VFX Platform Compliant
gcc (Linux only) 11.2.1 Yes
glibc (Linux only) 2.28 Yes
Minimum Deployment Target (macOS only) 10.15 Yes
Visual Studio (Windows only) 2022 Yes
Windows SDK (Windows only) 10 Yes
C++ API/SDK C++17 Yes

Houdini 21.0

Getting started

Using Houdini

  • Geometry

    How Houdini represents geometry and how to create and edit it.

  • Copying and instancing

    How to use copies (real geometry) and instances (loaded or created at render time).

  • Heightfields and terrains

    How to use Houdini’s heightfield tools to generate realistic terrains.

  • Animation

    How to create and keyframe animation in Houdini.

  • Digital assets

    Digital assets let you create reusable nodes and tools from existing networks.

  • Import and export

    How to get scene, object, and other data in and out of Houdini.

  • MPlay viewer

    Using Houdini’s stand-alone image viewer.

Character FX

  • Character

    How to rig and animate characters in Houdini.

  • Crowd simulations

    How to create and simulate crowds of characters in Houdini.

  • Muscles and tissue

    How to create and simulate muscles, tissue, and skin in Houdini.

  • Hair and fur

    How to create, style, and add dynamics to hair and fur.

  • Feathers

    How to create highly realistic and detailed feathers for your characters.

Dynamics

  • Dynamics

    How to use Houdini’s dynamics networks to create simulations.

  • Vellum

    Vellum uses a Position Based Dynamics approach to cloth, hair, grains, fluids, and softbody objects.

  • Pyro

    How to simulate smoke, fire, and explosions.

  • Fluids

    How to set up fluid and ocean simulations.

  • Oceans and water surfaces

    How to set up ocean and water surface simulations.

  • MPM

    How to simulate different types of solid materials (such as snow, soil, mud, concrete, metal, jello, rubber, water, honey, and sand).

  • Destruction

    How to break different types of materials.

  • Grains

    How to simulate grainy materials (such as sand).

  • Particles

    How to create particle simulations.

  • Finite elements

    How to create and simulate deformable objects

Pipeline

  • Executing tasks with PDG/TOPs

    How to define dependencies and schedule tasks using TOP networks.

  • HQueue

    HQueue is Houdini’s free distributed job scheduling system.

  • Houdini Engine

    Documents the Houdini Engine C, Python APIs, and Houdini Engine plugins

  • Machine Learning

    Houdini provides a platform for machine learning which supports synthetic data generation, preprocessing, training models, exporting trained models, and deploying trained models

Nodes

  • OBJ - Object nodes

    Object nodes represent objects in the scene, such as character parts, geometry objects, lights, cameras, and so on.

  • SOP - Geometry nodes

    Geometry nodes live inside Geo objects and generate geometry.

  • DOP - Dynamics nodes

    Dynamics nodes set up the conditions and rules for dynamics simulations.

  • VOP - Shader nodes

    VOP nodes let you define a program (such as a shader) by connecting nodes together. Houdini then compiles the node network into executable VEX code.

  • LOP - USD nodes

    LOP nodes generate USD describing characters, props, lighting, and rendering.

  • ROP - Render nodes

    Render nodes either render the scene or set up render dependency networks.

  • CHOP - Channel nodes

    Channel nodes create, filter, and manipulate channel data.

  • COP - Copernicus nodes

    COP nodes provide real-time image manipulation within a 3D space.

  • TOP - Task nodes

    TOP nodes define a workflow where data is fed into the network, turned into work items and manipulated by different nodes. Many nodes represent external processes that can be run on the local machine or a server farm.

  • APEX - APEX nodes

    APEX nodes provide operations for building up the functionality of APEX graphs, which are used in KineFX to create character rigs and perform other geometry manipulation.

Scene building, Karma rendering, Image processing

  • Solaris and Karma

    Solaris is the umbrella name for Houdini’s scene building, look development, and Karma rendering tools based on the Universal Scene Description (USD) framework.

  • Copernicus

    Houdini’s 2D and 3D GPU image processing framework.

  • Compositing

    Houdini’s compositing networks let you create and manipulate images such as renders.

Mantra rendering and shading

Reference

  • Menus

    Explains each of the items in the main menus.

  • Viewers

    Viewer pane types.

  • Panes

    Documents the options in various panes.

  • Windows

    Documents the options in various user interface windows.

  • Stand-alone utilities

    Houdini includes a large number of useful command-line utility programs.

  • APIs

    Lists all the reference documentation for the ways you can program Houdini.

  • Python scripting

    How to script Houdini using Python and the Houdini Object Model.

  • Expression functions

    Expression functions let you compute the value of parameters.

  • HScript commands

    HScript is Houdini’s legacy scripting language.

  • VEX

    VEX is a high-performance expression language used in many places in Houdini, such as writing shaders.

  • Properties

    Properties let you set up flexible and powerful hierarchies of rendering, shading, lighting, and camera parameters.

  • Galleries

    Pre-made materials included with Houdini.

  • Houdini packages

    How to write and combine multiple environment variable definition files for different plug-ins, tools, and add-ons.

  • hwebserver

    Functions and classes for running a web server inside a graphical or non-graphical Houdini session.