Applications
HoudiniUnreal EngineUnity 3DNukeMayaBlenderZBrushPythonMixed RealityMachine LearningGraphic DesignExtrasAboutProgram Settings
File Locations
Default location for working files packaged with Houdini that can be used for reference or quick access:
C:\Program Files\Side Effects Software\Houdini[version]\houdini\picDefault location for digital assets:
C:\Users\username\Documents\houdini18.0\otls\digitalAssetName.hdalcDefault location for defining environment variables:
C:\Users\[username]\Documents\houdini[version]\houdini.envDefault location for sprites and sample images:
C:\Program Files\Side Effects Software\Houdini<version>\houdini\picView Current Configuration
Start Menu > Side Effects Software > Command Line Tools
Access configuration with the following command:
hconfig -apEnvironment Variables
List of available variables:
Environment variables
See how to set environment variables. HOUDINI_STATS_API_URL This variable controls which web URL Houdini sends anonymous usage statistics to. The default value is http://www.sidefx.com/stats/api. HOUDINI_DSO_ERROR Determines if DSO/DLL errors on plug-ins will be printed out to the console. This can help in debugging custom operators. By default this is disabled.
www.sidefx.com
Setup and special characters:
Environment variables
Houdini uses environment variables for various purposes, such as defining paths (sets of directories in which Houdini looks for certain types of files), commonly used directories (such as $HFS, the install location of Houdini) and for obscure or highly technical settings. See the list of environment variables in Houdini.
www.sidefx.com
$HIP & $JOB
Coordinate location of $HIP and $JOB paths for respective project file by accessing Edit > Aliases and Variables. In the Variables tab, define paths as necessary by selecting line item, modifying using text field at bottom right, and pressing Enter key to update.
Paths
$HIP: Map to working project file in Project drive.$JOB : Map to project's sim and output folder in Overload drive.Editing Environment Variables
In an instance where an environment variable needs to be updated to differ than those already set by the .env file noted above, the following processes allow for editing them.
Method 1
In this first method, the edits are made within an existing Houdini session and can be made to overwrite the ones in the .env file without having to restart Houdini. It can also be used to take effect in a new project within the open Houdini session in which the edit is made. To check the status of an environment variable within Houdini, access the Texport panel and input the name of the variable.
Textport
-> $HOUDINI_OTLSCAN_PATH
@/otls;D:/path/to/env/set/pathTo change the value/s of the environment variable, access the Python Shell panel and use the putenv() function to edit the value. Other relevant functions include getenv() and unsetenv().
Python Shell
hou.putenv("HOUDINI_OTLSCAN_PATH", "D:/updated/path/to/otls")Reference: https://www.sidefx.com/docs/houdini/hom/hou/putenv.html
Lastly, check the Textport panel again to see the updated value for the edited environment variable.
Textport
-> $HOUDINI_OTLSCAN_PATH
D:/updated/path/to/otlsMethod 2
Packages
Link to External Editor
Set up by defining environment variables for routing to the external editor, such as JetBrains PyCharm.
EDITOR: Path to external editor executable.
VISUAL: Path to external editor executable; overrides EDITOR variable if defined.
External editor can also be defined by accessing Edit > Preferences > Set External Text Editor, and navigating to the external editor executable.
Access the external editor from within a Python context via RMB click > Expression > Edit in External Editor.
A hotkey can be defined for this action via Edit > Hotkeys... and navigating within Context to Houdini > Panes > Parameter Fields and Labels > Edit in External Editor (under Action).
Preferences
Image Previews in File Browser
To disable showing images in file browsers, the following sets the default:
Edit > Preferences > General User Interface
Disable the option Show Images for Image Files in File Browsers.
Project Settings
Setup Takes
Use the Main take as the low quality version for testing, simulating fast, and debugging. But then simulate and render finalized versions with a high quality HQ take. Open up relevant parameters in HQ so they can be edited.
File Naming Convention
References
- File Name Expressions: https://www.sidefx.com/docs/houdini/render/expressions
- Integrating Python Expressions: https://www.sidefx.com/docs/houdini/expressions/pythonexprs.html
Custom Configurations
Utilities
The following link is to my collection of utilities for use with Houdini. These are referenced in the scripts noted below.
morphingdesign/houdiniPython
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github.com
Startup Scripts
Session
Reference: https://www.sidefx.com/docs/houdini/hom/locations.html#startup
Nodes
Reference: https://www.sidefx.com/docs/houdini/hom/locations.html#node_event_files
Tools
Script
Name: scene_rnd
User Interface
Sticky Notes Text Color
When sticky notes are converted to light gray (2nd from right at bottom), the text is set to a gray color and stays as such when changed to other colors. However, when changed to the darkest gray (2nd from left at bottom), the text is reverted back to white and stays as white whenever other colors are selected, with the exception of the aforementioned light gray, which reverts text back to the gray color.
Panel Links
Panels can be linked and locked using the lock icon at the top right of each panel. To link panels, use the lock icon to select from one of the available numbers and coordinate the panel to link with the same number. This example shows the two left panels linked with 1 and the two right panels linked with 2 to consistently link the nodes with their corresponding properties. This strategy can be applied other panels also, such as Scene, Geometry spreadsheet, etc.
Quick Marks
Items marked as MyCGDoc Production Protocol are my personal custom settings I have defined in my current production methodology. They can be customized to suit one's own preferences.
Quickly cycle through network views using the user-defined numbers assigned to them. Reference Keyboard Shortcuts.
- Objects Network:
1 - Shader Network:
2 - Motion FX Network:
3 - Materials Network:
4 - Outputs Network:
5
Scene View Settings
Display Options (Shortcut: D)
Guides Tab
Display time and geo information at bottom right corner of Scene View panel by accessing Display Options > Guides > Show Time and Geometry information.
Geometry Tab
Particles: Display Sprites: Disable to optimize workflow.
Wire Width: Used to define the width of the geometry wireframe in the Scene View. This is most noticeable for templated geometry. Together with a Color SOP, the wireframe of templated geometry can be custom colored also, as exemplified in the following link: Custom Template Geometry Wireframe Color & Width
Scene View Panel
Configure cameras to display key viewport information using a Viewport Comment attached to each camera. More info about this in the Camera node section.
Network Wiring Styles
Default style: Open Display Options
Change style: View > Change Network Wiring Style or Shift + S
Rendering Management
Before processing a render job, verify that the following are clearly set for the specific scene and render:
Redshift
Items marked as MyCGDoc Production Protocol are my personal custom settings I have defined in my current production methodology. They can be customized to suit one's own preferences.
Object Network
Redshift OBJ Settings
Disable Progressive Rendering; inapplicable when outputting AOVs
Lights
Takes
Redshift ROP Settings
Frames
$F4 in File PathMantra
Settings
Timeout Detection and Recovery (TDR)
TdrDelay & TdrDdiDelay: Configured and set to 240.
Motion Blur
If motion blur for particles is applied, verify that the motion blur settings are activated in both the Redshift ROP settings and the particles geo SOP settings, particularly the blur from the particles’ velocity attribute.
Geo SOP
Redshift SOP
Render Noise
Disable Randomize Pattern On Each Frame for animations to mitigate flickering.
Source
Denoising
Rendering effects like depth of field, motion blur, global illumination, area lighting and others require the renderer to shoot multiple rays into the scene. If a low number of rays ("samples") are shot, the final result can appear noisy ('grainy'). The typical solution to this is increasing the number of samples (as explained here), but that means longer render times.
docs.redshift3d.com

Materials
Double-sided Material
RS Ray Switch
Use Enable Front/Back to specify texture streams for both front and back face of material applied to single-sided geometry.
Render Passes
Y-ramp Pass
Custom Depth AOVs in Redshift
Source guide references Redshift in Maya, but same process applies to Redshift in Houdini, including the RS State process.
Source: https://vimeo.com/250911062
Alembic File Management
Preserve Geo Groups In Alembic Output
Export Process
Use a Name node to add a name attribute aligning with each specified group.
In the ROP Alembic Output, enable Build Hierarchy From Attribute by setting Path to the name attribute. This will preserve the groups within the geometry so that they can be accessed individually when accessed within the Alembic output.
Import Process
Use the Alembic node to import the content and access groups by setting Primitive Groups to Name Group Using Shape Node Full Path. This reads each of the corresponding path attribute values and assigns each to their own primitive group.
Troubleshooting & Resolutions
Licensing
Windows Updates Conflicts
Date of Issue: 20210209
Issue: In a single instance, some Windows updates disabled the Houdini License Server or somehow made it invalid
Resolution: Reinstalling the Server Key resolved this issue.
Source: https://www.sidefx.com/faq/question/29/
GPU Antialiasing
Date of Issue: 20210222
Issue: The following prompt appeared when attempting to render with Redshift in Houdini:
Resolution: Setting the custom program antialiasing settings to Application-controlled allowed for the program to disregard the global settings.
On This Page
- Program Settings
- File Locations
- View Current Configuration
- Environment Variables
- $HIP & $JOB
- Paths
- Editing Environment Variables
- Link to External Editor
- Preferences
- Image Previews in File Browser
- Project Settings
- Setup Takes
- File Naming Convention
- Custom Configurations
- Utilities
- Startup Scripts
- Session
- Nodes
- Tools
- Script
- User Interface
- Sticky Notes Text Color
- Panel Links
- Quick Marks
- Scene View Settings
- Guides Tab
- Geometry Tab
- Scene View Panel
- Network Wiring Styles
- Rendering Management
- Redshift
- Object Network
- Redshift OBJ Settings
- Lights
- Takes
- Redshift ROP Settings
- Frames
- Mantra
- Settings
- Timeout Detection and Recovery (TDR)
- Motion Blur
- Geo SOP
- Redshift SOP
- Render Noise
- Source
- Materials
- Double-sided Material
- RS Ray Switch
- Render Passes
- Custom Depth AOVs in Redshift
- Alembic File Management
- Preserve Geo Groups In Alembic Output
- Export Process
- Import Process
- Troubleshooting & Resolutions
- Licensing
- Windows Updates Conflicts
- GPU Antialiasing