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Enabled | Activates or deactivates denoiser calculation for the next render. | |
Denoised Image | Here you can specify the path, name and format of the denoised image. | |
Apply DenoiseApply Denoiser | In this drop-down menu you can choose to calculate the denoised image at each SL step starting with the one set in the spinbox (8 by default option) or only at the end of the render.Denoise Shadow | This option allows to additionally denoise shadow channel (only available with "Auto configure" set to "Accurate") |
Use GPU | If on, the denoised image will be calculated using the GPU (much faster usually), if not it will use CPU. Check its section below for more information. | |
Tiling | This feature makes Maxwell calculate the denoised image by tiles or pieces instead of trying to calculate it all in one go; this reduces memory requirements a lot. The Size spinner lets you choose the maximum tile size that will be used. Check its section below for more details. | |
Auto Configure | If activated, this option will set This option sets all the required channels and options automatically so the denoiser can work; it comes in two flavours: Fast and Accurate (explained in its section below). | |
Re-Denoise (only in Maxwell Render)Denoise Shadow | This option allows to redo denoise calculation after you have made changes to Multilight sliders, so you can produce a denoised image with the new light configuration. |
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Two renders.
It's important to understand that the Denoiser needs to launch two renders and benefits from some extra channels so, when you activate the denoiser, render routine changes in order to get this information.
Don't worry, everything is done under the hood automatically and at the end, you will get the work of both renders combined in a merged mxi plus the denoised image.
You can get information the progress of both renders in Render Progress and Render Info toolbars and in Console:
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Toolbar with two passes information
Apply Denoise - Each SL or At end.
There are two options to show denoised image:
Each SL
In this mode, Maxwell will calculate first pass (first render) until it gets to the SL set in the spinbox ("starting with SL") and then the second pass (second render) will kick in;
when both passes have reached SL4 (default setting) the first denoised image is calculated and shown in render viewport as if it was an extra channel (but with a square icon instead of a circle);
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after that, the first pass is resumed until it reaches the next SL and then the second pass is also resumed; when both passes reach the same SL another denoised image is calculated and the process continues with this loop until it reaches the final SL or the process is stopped.
When the render is finished you will get the denoised image and both not-denoised passes will be merged into one file mxi and the image saved in the specified output format, so you get the result of all the work done.
All intermediate denoised images are calculated with a faster and lower quality method, but the final denoised image is always top quality.
This method allows to monitor if the render needs more time or not while you see the denoised result. It's the most interactive method.
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additionally denoise the shadow channel (it’s only available with "Auto configure" set to "Accurate", as it requires the Shadow channel to be active). | |
FINE-TUNING OPTIONS | |
Color Influence 1 | Controls how much high-frequency detail of the render pass will be retained; this affects how the edges are handled. Low values mean more feature preservation <> High values mean more smoothing. |
Color Influence 2 | Controls how much mid-frequency detail of the render pass will be retained; this affects how color information is handled. Low values mean more feature preservation <> High values mean more smoothing. |
Feature Influence | Controls the influence of the extra passes (Normals, Position, Reflectance and Shadows). Low values mean more feature preservation <> High values mean more smoothing. |
Final Pass | Controls the influence of the final pass that affects color differences. Low values mean more feature preservation <> High values mean more smoothing. |
Filter Radius | Defines the area around the pixel taken into account when calculating its color. It can change the overall look of the smoothing and how the noise is handled. Again, low values mean more feature preservation, but also constrains the information available for the calculation <> High values mean more smoothing. |
Firefly Remover | This will detect and reduce the spread of high energy pixels (very bright pixels that usually come from SSS materials or caustics). |
Workflow
In order to use the Denoiser, you only have to activate it before launching the render. Maxwell, by default, will activate some extra channels that help the Denoiser distinguish the objects' shapes and textures so it preserves as many details and features of the image as possible.
After launching the render, you will notice the Denoiser channel is active, as well as the Normals, Position and Reflectance channels (the Reflectance channel won’t show if you are using the GPU engine to render the image).
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Hover the mouse over the D icon to see the Denoiser channel in the Render area.
The MXI file will include the Denoiser channel as it happens with other channels, so you can open it, make changes to Multilight and refresh the Denoiser channel with the new lighting setup as many times as you want. You can also, resume the render or merge the MXI files from different computers.
You can use the Refresh R and D toggles to choose if you want to refresh the render, the denoiser or both channels:
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Refresh toggles set to refresh only the Denoiser channel
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Now Maxwell does not need to launch two render for the Denoiser to work, so the whole process is less complicated, less prone to problems and more reliable. |
Apply Denoise - Each SL or At end.
When the Denoiser is active, you can choose to get updates of the denoised image during the render (Each SL), which is more interactive, or only at the end of the render (At end), which is faster.
Each SL
In this mode, Maxwell will calculate the denoised image at each SL update.
You can specify the first SL that will get a denoised image update in the Start with SL spinner (by default it’s set to 8).
This method is more interactive as allows the user to check how the denoised image looks like during the render, however, it wastes computing time while generating the intermediate denoised images.
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Render routine scheme at "Each SL" mode.
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Render routine scheme at "At end" mode.
Use GPU
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Regardless of the render engine you use, the Denoiser is capable of calculating the denoised image using GPU or the CPU. You Unlike with the render engine, you can use Nvidia, AMD and Intel graphics cards; it works with CUDA (Nvidia) and this is the fastest, but it can also work using OpenCL either in GPU (Nvidia, AMD or Intel) or CPU.
The default option is GPU as it is usually much faster; the Denoiser will first try to use CUDA, if it doesn't find a compatible card, it will automatically fallback to OpenCL GPU (usually with AMD and Intel cards) and then OpenCL with CPU.
It’s important to be aware that when using the GPU, the graphics card memory will be used and, if the CPU is used, the RAM of the computer will be used to compute the denoised image.
These would be the minimum system requirements for Denoiser:
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| Note |
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In the case you get an error message when using CPU about OpenCL ICDs, it means Maxwell cannot find valid OpenCL drivers installed on your machine; usually, those drivers are included with your graphics card drivers, so I would try updating the drivers to the latest. If that doesn't help, it will probably be solved by installing this Intel's OpenCL runtime package: Windows: opencl_runtime_18.1_x64_setup.msi Linux: opencl_runtime_18.1.0.013.tgz This could also solve the error "OpenCL exception" shown when using the latest AMD processors. |
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The Size spinner next to it sets the maximum size of the tiles, so you can control the memory that will be used in the process. This allows you to denoise the render on virtually any device. Please, notice that smaller tiles mean some more calculation time. This can be changed after the render has finished.
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all channels in EXR 32 format;
if you use the Normals channel it should be in Camera mode;
If you use the Position channel it should be in World mode;
if you want to use the Shadow channel, it is recommended to turn on the Shadow option in all materials (in Global Properties) except for emitters.
Fine-tunning options
Now Maxwell exposes some parameters to that allow fine-tune the Denoiser resulttuning the Denoiser result.
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Fine-tunning parameters
Except for the Firefly Remover, all these parameters work as a trade-off between preserving detail and smoothing the image. In general, low values mean more feature preservation (the drawback is that some noise or artifacts may be visible) while high values mean more aggressive smoothing, however, some details may be lost.
The Denoiser initially computes the render pass (affected by Color Influence 1 and 2 parameters), then adds the different extra channels to the calculation (affected by the Feature Influence parameter) and then runs an additional final pass (affected by the Final Pass parameter). All this process is globally affected by the Filter Radius parameter.
The Color Influence 1 parameter (from 0 to 1; default: 0.45) controls how much high-frequency detail of the render pass will be retained or smoothed; this means the edges of high contrasted areas will be affected by it. The effect of this parameter is quite subtle.
The Color Influence 2 parameter (from 0 to 1; default: 0.45) controls how much mid-frequency detail of the render pass will be retained; this affects how the color information is handled.
The Feature Influence parameter(from 0 to 1; default: 0.60) controls the influence of the extra passes (Normals, Position, Reflectance and Shadows). If you are losing detail on the textures, this is a good parameter to lower down, so the information in the channels takes more relevance (as the textures usually show up in the reflectance channel).
The Final Pass parameter (from 0 to 1; default: 0.45) controls the influence of the extra final pass and affects color differences.
The Filter Radius parameter (from 2 to 50; default: 10) defines the area around the pixel taken into account when calculating its color. It can change the overall look of the smoothing and how the noise is handled. Again, low values mean more feature preservation, but also constrains the information available for the calculation and may produce some artifacts when it goes too low <> High values mean more smoothing so it can wash away too much detail. If you want to get the same denoising effect on a hi-resolution image as the one you obtained on a low-resolution one, you might want to increase this value, so the whole effect “scales” up.
The Firefly Remover will detect and reduce the spread of high-energy pixels (very bright pixels that usually come from SSS materials or caustics). It has a minor impact on calculation time.
Particularities
Auto configure will always be set to "Fast" when using GPU render engine.
When using Extra Sampling feature, only "At end" method will be available.
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