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- It is uncommon needing to render beyond SL 19 - 20.
Sampling Level vs Time
There are two ways to stop a render in Maxwell Render: by setting a Sampling Level or by setting a Render Time (in minutes). If you set both parameters, the render will stop when the first one is reached. This double approach gives you a lot of flexibility to control the quality and time invested in rendering. For example if you want to quickly compare a few renders of a scene you can set the time low (ex. 10min) and the SL high (ex. 15). In this case it is improbable the render will reach SL 15 in 10 minutes, so the render will stop after 10 minutes. For a final render you should set the SL to the desired level and set the time to a high value (ex. 999 minutes). Maxwell Render will stop when the SL is reached. If the render needed a higher SL you can always resume the render. See How to resume a render for more information.
Incremental render view update
At the beginning of the render, the Sampling Levels increase faster, and the main render view in Maxwell.exe will update with each new SL reached. As the render goes on however, it will take longer and longer to reach the next SL, and so the main render view will update every 10 minutes. You can also choose how often to update the main render view from the Maxwell.exe preferences (File>Preferences). It can be useful to set this time to a higher minimum because each time the render view updates, Maxwell writes a new version of the MXI file to disk and the rendering stops until it has successfully written that MXI, then resumes the render. To avoid this pause/resume/pause/resume especially at the beginning of the render, you can set a minimum write time to 15 minutes or more for example. Please see the Preferences section at the bottom of the User interface and menus page for more info.
The MXI file format
Every time Maxwell renders an image, it keeps all lighting calculations in a special file format called MXI. Besides holding high dynamic range image data, the MXI file also holds additional information that allows for example to resume a render, or change the scene lighting using Multilight. It also contains any extra render channels you have selected when adding the render, that can always be extracted from the MXI and saved as regular bitmap.
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