Houdini 20.0 Reference Stand-alone utilities


Removes noise from an image file.

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idenoise infile outfile [options]...


You can install libraries that use various techniques (such as machine learning and GPU computation) to provide very fast and high-quality denoising. This utility is a convenient front-end to use those libraries to denoise a single image.


The Denoise AI compositing node lets you apply the same denoisers as this utility in a compositing network.

This utility currently supports Intel Open Image Denoise and the NVIDIA OptiX Denoiser. You must be on a supported platform and have the chosen denoising library installed for this utility to work.

  • Houdini ships with OIDN so it will be available if you are in a Houdini shell environment.

  • The NVIDIA OptiX Denoiser only works with NVIDIA cards. It is now included with the NVIDIA driver (version 435 or later). If you have an earlier driver version, you can choose Render ▸ Download NVIDIA OptiX Denoiser in Houdini to download the library automatically.

You can specify multiple image planes to denoise simultaneously.

Some denoising libraries can use normals and/or albedo to get a better sense of the image, guiding how and where it reduces noise. This utility lets you optionally specify the name of a normal plane and the name of an albedo plane to use as input for the denoiser.



List all available denoisers.

-d denoiser

Denoiser to use. This must be one of oidn (Intel Open Image Denoise) or optix (NVIDIA OptiX Denoiser). The default is oidn.

-n normal_name

Name of the normal plane in the image file to use as input to the denoiser. If you don’t supply this option, the denoiser will not use a normal plane.

-a albedo_name

Name of the albedo plane in the image file to use as input to the denoiser. If you don’t supply this option, the denoiser will not use an albedo plane.

-m motionvectors_name

The name of the motion vectors plane. Required by OptiX to eliminate temporal noise.

-p previous_frame

The path to the previous denoised frame. In the first frame of a sequence, it could be set to the noisy beauty image of the first frame instead of the denoised version and all flow vectors set to zero. Required by OptiX to eliminate temporal noise.

--extra_aovs plane_1 plane_2 … plane_n

Space-separated names of the extra image planes to pass to the denoiser (other than the specific normal, albedo, etc.). These AOVs are not altered, but available to the denoiser for reference.

--aovs plane_1 plane_2 … plane_n

Space-separated names of the image planes to denoise in the output image. If not specified, C, Cf, and color are used by default.

--exrmode mode


Use HOUDINI_OIIO_EXR variable.


Use classic driver.


Use improved driver.

--options json

The argument is a JSON-formatted object. You should enclose the JSON text in quotes to prevent the shell from trying to interpret any special characters. For example:

> idenoiser -d oidn --options "{'auxareclean': true}" infile.exr out.exr
> idenoiser -d optix --options '{"blendfactor": 1.2}' infile.exr out.exr

You can specify the following keys in the option JSON:








Sets the cleanAux filter parameter, for further improving quality when the auxilary feature (albedo, normal) planes are noise-free, as described in the OIDN documentation. Default is false.




Whether to pre-filter the albedo and normal auxiliary planes before de-noising the image planes. Default is false.




Blend between the denoised image (0.0) and the original image (1.0). For example, 0.25 is like overlaying the original image with 25% opacity onto the denoised image. Default is 0.0.


Denoise the color plane of example.exr using Intel OIDN:

idenoise example.exr denoised.exr

Denoise the diffuse and indirectDiffuse planes of example.exr, with the NVIDIA OptiX Denoiser, using the hitN normal plane as input to the denoiser:

idenoise example.exr denoised.exr -d optix -n hitN --aovs diffuse indirectDiffuse 

Denoise in temporal denoising mode to eliminate motion blur noise properly.

idenoiser -d optix -m motiovectors -p previous_frame.exr --options '{"blendfactor": 1.2}' infile.exr out.exr
See also

Stand-alone utilities

  • abcconvert

    Convert between Alembic formats.

  • abcecho

    Print information about an Alembic file.

  • abcinfo

    Print information about an Alembic file.

  • chchan

    Copies channel collection to/from action channel format.

  • chcp

    Copies channel collection file to another format.

  • chinfo

    Prints information about a channel collection file.

  • claudio

    Copies CHOP data (clip) to/from audio formats.

  • clchan

    Copies CHOP data (clip) to/from action channel format.

  • clchn

    Copies CHOP data (clip) to/from channel collection format.

  • clcp

    Copies CHOP data (clip) to another format.

  • clinfo

    Prints information about a CHOP data (clip) file.

  • dsmconvert

  • dsmmerge

  • dsparse

    Parses and displays dialog scripts.

  • gabc

    Convert between Alembic and Houdini geometry.

  • gconvert

    Convert between Houdini polygon formats.

  • gdxf

    Converts DXF polygons to/from Houdini format.

  • geodiff

    Display Geometry Differences.

  • geps

    Converts EPS files to Houdini polygon format.

  • giges

  • ginfo

    Prints polygon file statistics.

  • glightwave

    Converts LightWave files to/from Houdini format.

  • gpdb

    Converts .pdb files to/from Houdini format.

  • gplay

    Geometry viewer.

  • gply

    Converts .ply files to/from Houdini format.

  • gptex

    Makes a ptexture image file from a geometry file.

  • greduce

    Reduces polygons in a file.

  • gwavefront

    Converts .obj files to/from Houdini format.

  • hcollapse

    Collapses a directory structure.

  • hcpio

  • hexpand

    Expands hip files into a directory structure.

  • hkey / License Administrator

    Opens a graphical user interface for viewing and managing licenses and license server options.

  • hoiiotool

    Swiss-army knife of image operation tools.

  • hotl utility

    Command line utility to work with .hda/.otl files.

  • hrender

  • hsc

  • hscript

    Command line HScript interpreter.

  • hserver

    Houdini communicates through this proxy server to the sesinetd licensing daemon.

  • htexcache

    Query or modify the disk texture cache.

  • husk

    Command line utility for rendering a USD file using Karma or some other Hydra client.

  • i3dconvert

  • iautocrop

    Crops images based on pixel values.

  • icineon

    Convert images from 10-bit Cineon format to an 8 bit format.

  • icomposite

  • iconvert

    Converts an image of one type to another type.

  • icp

    Isolate a region of an image in a new image.

  • idenoise

    Removes noise from an image file.

  • idiff

    Display Image Differences.

  • iflip - Flip Image

  • iinfo

    Outputs information about an image.

  • ilut

    Generates a lookup table (LUT) from standard channel formats or another LUT.

  • ilutcomp

    Generates a single lookup table (LUT) from from two LUTs.

  • ilutinfo

    Prints information about a lookup table (LUT) file.

  • imaketx

    Creates mipmapped .exr or .rat textures from image files.

  • imdisplay

    Sends an image to an mdisplay window.

  • iprint

    Prints the RGBA values for an image as text.

  • iquantize

    Reduces the number of colors in an image.

  • isixpack

    Generates an environment/reflection map from six images representing the six sides of a cube, or a cross image.

  • itilestitch

    Assemble a series of image files with crop windows into a single image.

  • izg

    Converts Z-depth images to 8-bit grayscale images.

  • Launcher

    The Houdini Launcher downloads, installs, upgrades, and uninstall Houdini and its components.

  • mcacclaim

    Converts an Acclaim motion file to a Houdini script and channel file(s).

  • mcbiovision

    Converts a BioVision motion file to a Houdini script and channel file(s).

  • mcmotanal

    Converts a Motion Analysis TRC motion file to a Houdini script and channel file(s).

  • mcp

    Convert an image sequence to a movie file.

  • minfo

    Prints information about movie files.

  • mqserver

    Message Queue Server for PDG/TOPs

  • py23convert

    Convert Python 2 expressions in HDAs to Python 2/3.

  • renderstatsoverlay

    Generates a (possibly scaled down) version of a rendered image with render statistics baked in.

  • renderstatsreport

    Generates an HTML page containing render statistics from an EXR image.

  • sesictrl

    Sets Houdini license server options from the command line.

  • sesinetd

    The Houdini license server. This program runs in the background managing Houdini licenses.

  • siminfo

    Prints simulation cache file statistics.

  • spiff

    Display Text Differences.

  • spy

    Shell utility for navigating the UNIX filesystem.

  • usdview

    Command line utility for viewing and inspecting USD scenes.

  • vexcache

    Query or modify the VEX compile cache.

  • vexexec

    Execute a cvex shader.