These buffers are normally hidden from Redshift's Render View but if you check "Show additional buffers in RenderView", those buffers will appear in the Render View's AOV list and will be previewable. While Redshift is rendering, it generates some aditional images ("buffers") which are essential for the denoising process. The AOVs used by Altus are: Diffuse Albedo, World Position and Bumped Normal Unticking that option means that the user will manually add the necessary AOVs. When "Automatically Create AOVs" is enabled, Redshift will automatically add any AOVs that Altus needs to achieve its denoising results. We recommend using the "Altus Single Pass" denoise engine, especially if you are a new Altus user!Īltus can achieve more accurate results with the use of additional Redshift AOVs. This approach is much more natural as it doesn't double the frame time and doesn't involve the user having to do any tricks like the above tweaking of the unified sampling settings. This lowered render times but also meant that both frames would be noiser - but that was ok because Altus would clean the noise.Īt a later point in the Altus-Redshift integration, Innobright introduced their Single Pass technique which can determine per-pixel noise in a single render pass. The drawback of this approach is that the frame takes twice as long to render because it gets rendered two times! Some users got around this by tweaking their unified sampling settings and increasing the error threshold right before denoising. Altus required two separate rendered frames to determine where the noise is. In the early days of the Altus-Redshift integration, there was no Single Pass mode available in Altus so the only option available to users was the Dual Pass approach. "Altus Dual Pass" means that the frame will be rendered twice before denoising. "Altus Single Pass" means that the frame will be rendered once and then Altus will execute denoising. To enable denoising with Altus simply select "Altus Single Pass" or "Altus Dual Pass" for the denoise engine and then do bucket rendering (Altus does not work in progressive!) using the Render View. This workflow is particularly important to follow when rendering animations. In other words, the user should still tune their settings for an 'ok' level of noise and then employ denoising to make the frame perfect. In animations, the noise might appear as ugly 'flickering splotches' which can be more visually distracting that the original noise!įor the above reasons, we recommend that denoising is primarily used to clean "the last few percent" of noise.In the case of OptiX, these artifacts might look like brush paintstrokes It might produce weird visual artifacts.It might 'oversmooth' certain parts of the image and lose considerable amounts of detail, especially in textures or small geometry details.noise will still be present after denoising) The denoise might simply fail to denoise the image to a sufficientl degree (i.e.It should be noted that denoising is not a silver bullet! If the rendered image is excessively noisy, denoising can fail in multiple different ways: Sometimes it can't detect noise as noise because it hasn't been trained with that particular case, so it has trouble cleaning it
Is very fast and can be used in interactive rendering while editing the scene Uses production-proven algorithms so results can be more predictableĭenoising takes several seconds to compute so it's not possible to use in an interactive fashion OptiX pros and cons On the other hand, NVidia's OptiX AI denoiser uses a deep learning algorithm that has been trained with tens of thousands of images.Įach of these two denoising solution has pros and cons: Altus pros and cons Innobright's Altus uses a traditional and production-proven techniques to achieve its denoising effect.
Redshift supports two different denoisers: Innobright's Altus and NVidia's OptiX AI denoiser. In both cases, though, it should take less time than what Redshift would need to render the scene if samples were significantly higher. The process can be fast (in the case of NVidia's OptiX, it's near real-time) or can take a good few seconds.
"Denoising" refers to a rendering technique that removes noise from an image. The typical solution to this is increasing the number of samples (as explained here), but that means longer render times.Īn alternative (and faster) solution is to use denoising instead. If a low number of rays ("samples") are shot, the final result can appear noisy ('grainy'). Rendering effects like depth of field, motion blur, global illumination, area lighting and others require the renderer to shoot multiple rays into the scene.
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