--- title: "Denoiser" canonical: "https://documentation.chaos.com/space/VSKETCHUP/109795092/Denoiser" format: markdown --- This page provides information on the Denoiser rollout. Overview The V-Ray Denoiser takes an existing render and applies a denoising operation to it after the image is completely rendered out via normal means. The denoising operation detects areas where noise is present and smooths them out. Because the V-Ray Denoiser operates on other render elements rather than being part of the rendering process itself, the denoising operation does not require rerendering of the scene. The Denoiser settings can be quickly changed and tested over and over to improve the result. Although V-Ray Denoiser is a render channel, for ease of access it is directly positioned under a separate rollout in the Settings tab. Don't search for the Denoiser in the Render Elements list. Just enable it from the Render rollout and if needed adjust its settings from the Advanced panel. Currently, the scene can contain only one Denoiser preset. Future versions of V-Ray supports simultaneously multiple Denoiser channels with different settings. Off On UI Path ||V-Ray Asset Editor|| > Settings > Denoiser     Denoising Engines VRayDenoiser offers a choice between the default V-Ray denoiser, the NVIDIA AI denoiser and the Intel Open Image denoiser (V-Ray's implementation of the Intel® Open Image Denoise). Each offers a different denoising algorithm that comes with different benefits. You can also opt to an Auto mode where the denoising engine changes based on the render mode. Auto – Changes the denoising engine depending on the render mode. Navigate to the advanced Denoising settings to change the default engine selection. V-Ray – V-Ray's denoising algorithm. It can utilize the CPU or the GPU (AMD or NVIDIA GPUs) to perform the denoising. It is consistent when denoising render elements, as it applies the same denoising operator to all render channels. This means that it is recommended for denoising the render elements to be used for compositing back the beauty image. In addition, it comes with a Denoiser Tool, which is recommended for denoising animation by using frame blending. NVIDIA AI – V-Ray's integration of NVIDIA's AI-based denoising algorithm. The NVIDIA AI denoiser requires an NVIDIA GPU  to work, regardless of whether the actual rendering was performed on the CPU or GPU. This means that rendering on the CPU still requires an NVIDIA GPU for denoising with the NVIDIA AI denoiser and has some advantages and drawbacks compared to the Default V-Ray Denoiser. For example, the  NVIDIA  AI denoiser performs the denoising faster but is not consistent when denoising render elements. This means that there are differences between the original RGB image and the one reconstructed from render elements that are denoised with the  NVIDIA  AI denoiser. It also doesn't support cross-frame denoising and is likely to produce flickering when used in animation. The Nvidia AI denoiser only works on Nvidia Maxwell and newer GPU architectures. Intel Open Image – V-Ray's integration of  Intel Open Image Denoise . The Intel Open Image denoiser works with your CPU device and does not use hardware acceleration. Like NVIDIA AI, the Intel Open Image denoiser is best suited for interactive rendering. These options reside in the  V-Ray Asset Editor  >  Settings  >  Render. Parameters Enable – Turns the Denoiser on or off. When enabled, it automatically adds the Denoiser as a Render Element. Engine – Allows choosing between the d efault V-Ray Denoiser , NVIDIA AI Denoiser and Intel Open Image Denoise . Interactive Engine – Determines the denoising engine to be used during Interactive rendering when the Auto denoising mode is selected. Preset  – (Available for V-Ray Denoiser engine only) Offers presets to automatically set the strength and radius values.  See the  Denoising Presets example  below . Default (Strength=1, Radius=10) – Applies a mid-level denoising. Mild (Strength=0.5, Radius=5) – Applies a more subtle level of denoising than the Default preset.   Strong (Strength=2, Radius=15) – Applies a stronger level of denoising than the Default preset. Custom  – Allows the  strength  and  radius  parameters to be set to custom values. Strength – (Available for V-Ray Denoiser engine only) Determines how strong the denoising operation is. Radius – (Available for V-Ray Denoiser engine only) Specifies the area around each pixel to be denoised. A smaller radius affects a smaller range of pixels. A larger radius affects a larger range, which increases the noise removal. Mode – (Available for V-Ray Denoiser engine only) Specifies how the results of the Denoiser are saved and presented in the VFB. Only Render Elements – All render elements required for denoising are generated but a denoised version of the image is not computed. VRayDenoiser and effectsResult render channels are not generated. Use this option if you plan to denoise a sequence of images using the standalone denoising tool and do not want to spend time on denoising during the actual rendering process. Hide Denoiser Channel – The VRayDenoiser channel is not present separately in the VFB. The effectsResult channel is generated with the denoised image. Show Denoiser Channel – The VRayDenoiser and effectsResult channels are generated. Panorama – When enabled, V-Ray determines whether the image is rendered with a spherical panorama camera, featuring a 360-degree field of view. This prevents visible seams caused by the denoising process. Update button  – (Available for V-Ray Denoiser engine only) Press to regenerate the denoiser channel without having to re-render the scene. Upscale – (Available for NVIDIA AI Denoiser engine only) When enabled, the image is rendered at half size to speed up its calculation while its denoised output is upscaled to full resolution. This results in cleaner and faster initial updates ideal for interactive rendering. NVIDIA's AI upscaling technology represents an advanced method based on machine learning that provides better results compared to standard image interpolation. Note that render elements without the Denoise option enabled are upscaled using standard interpolation. Light Cache Denoise – Applies denoising to the Light Cache prepass, producing a smooth image from the initial frame. NVIDIA AI Denoiser Intel Open Image Denoiser Example: Denoising Presets The example below illustrates how VRayDenoiser works using the presets. A purposely noisy render was set up using the Progressive Image Sampler Type with Render Time set to only 3 minutes to leave plenty of noise in the render.  RGB Color Render Element prior to denoising V-Ray Denoiser (Mild Preset) V-Ray Denoiser (Default Preset) V-Ray Denoiser (Strong Preset) V-Ray Denoiser (Custom Preset: strength : 5, radius : 10) V-Ray Denoiser (Custom Preset: strength :10, radius : 20) Denoising Animations When denoising animations, it is recommended to use the Standalone Denoiser Tool . Unlike the denoiser integrated in the UI, the standalone tool can do frame blending for animations, which reduces flickering. The integrated denoiser only works on the rendered frame and does not take the next and previous frame(s) into account, like the standalone tool does. To denoise an image sequence with  vdenoise  run the following command: vdenoise -inputFile="path\ o\sequence_????.ext 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:\ enderoutput , the full command is: vdenoise -inputFile="c:\ enderoutput\anim_????.exr When that command is run, the sequence is read and for each frame, the specified number of adjacent frames are also considered. A new output image is then written for each frame. Recommended settings: Mode set to only generate render elements . denoising engine set to  Default V-Ray denoiser . Render output set to vrimg or multichannel exr . The NVIDIA AI denoiser does not perform frame blending and is likely to produce flickering when denoising animations.     Notes Image denoising takes place after the frame has been rendered and doesn't show up until all rendering has finished. Textures or materials that have a purposely noisy look is not considered "noisy" by the Denoiser. They are not affected by the noise removal process. When using Progressive image sampler, the regularity of updates of the denoiser is controlled by the Update effects option in the Render rollout of the Settings menu .