Overview

The V-Ray installation includes a standalone denoising tool called vdenoise that can be used to denoise still images or animations outside of 3ds Max. This is especially useful for animations because the standalone tool can look at multiple frames at once and produce a better denoising result. The vdenoise tool works with either .vrimg or multichannel OpenEXR files and writes out files with the same format. You can write those files out of 3ds Max through the V-Ray raw image file output options in the V-Ray Frame Buffer rollout.

Installation

The vdenoise tool is a part of the V-Ray for 3ds Max installation and can normally be found in the folder C:\Program Files\Chaos Group\V-Ray\3dsmax Rx for yyy\tools. You can quickly open a command prompt in the folder where the vdenoise tool is located from Start Menu > Programs > Chaos Group > V-Ray for 3ds Max > Tools > Denoiser tool.

Generating the Needed Render Elements

The denoiser needs several render elements in order to work optimally. The easiest way to generate these render elements is to add the VRayDenoiser Render Element to your 3ds Max scene.

Required Render Elements

The required render elements are listed below. Add the VRayDenoiser or Denoiser Render Element to your scene to generate the necessary render elements automatically.The standalone denoiser will still run when some or all of these render elements are missing, but results might be too blurry.

For single pass RGB denoising:

• Noise level (named noiseLevel) - The denoiser relies heavily on this render element to provide information used during the denoising operation.

• Defocus amount (named defocusAmount)

• World positions (named worldPositions or wpp)

• World normals with bump mapping (named worldNormals)

• Diffuse filter (named diffuseFilter or VRayDiffuseFilter)

• Reflection filter (named reflectionFilter or VRayReflectionFilter)

• Refraction filter (named refractionFilter or VRayRefractionFilter)

Additional render elements for multipass per-render elements denoising:

• Atmosphere (named atmosphere or VRayAtmosphere)

• Background (named background or VRayBackground)

• Global Illumination (named globalIllumination or VRayGlobalIllumination)

• Lighting (named lighting or VRayLighting)

• Reflection (named reflection or VRayReflection)

• Refraction (named refraction or VRayRefraction)

• Specular (named specular or VRaySpecular)

Denoising Still Images

To denoise a single .vrimg or .exr image, use the following format for the command:

vdenoise -inputFile="path\to\image.exr"

where path\to\image.exr is the path and file name of the .vrimg or .exr file that you want to denoise.

For example, if the file you want to denoise is called render.exr and is located in the folder c:\renderoutput, the full command will be

vdenoise -inputFile="c:\renderoutput\render.exr"

Denoising Animations

To denoise a sequence of images, you must have all frames already rendered, as the denoiser needs to look at several frames at the same time. Use the following format for the command:

vdenoise -inputFile="path\to\sequence_????.exr"

where the question mark (?) replaces the digits in the sequence's file names.

For example, if the images in the sequence are named anim_0001.exr, anim_0002.exr, etc. and are located in the folder c:\renderoutput, the full command will be

vdenoise -inputFile="c:\renderoutput\anim_????.exr"

Denoiser Options

You can control the denoiser through optional switches on the command line. To list all available options in the command prompt window, run the denoiser without any arguments (vdenoise command) or use the -help switch:

vdenoise -help

The table below shows the optional switches, which are also displayed by the vdenoise -help command. To use a switch, precede the switch with a hyphen (-) and follow it with an equals sign (=) and the desired parameter, as shown in the table.

Output

When the standalone Denoise tool is run in the command prompt window, it outputs information about the process, including settings, warnings, progress, and files written.