Engine, sampler and other config related settings.
TODO describe the settings in detail, link to the general (exporter-agnostic) engine/sampler wiki pages where possible (and maybe create them).
LuxCore Device Settings
Allows to set the number or CPU threads and to select the OpenCL devices (graphics cards) that should be used, if OpenCL is available and an OpenCL engine is selected.
LuxCore Display Settings
Viewport Halt Time: How long the viewport render should run, in seconds. After this time, the render is paused until the scene is edited, which will cause it to restart and run until the halt time is reached again.
Final Refresh Interval: How often to update the film during final render, in seconds. The update refreshes all AOVs (passes) of the render layer that is currently being rendered. For long renders, it is recommended to use a long refresh interval, e.g. 600 (10 minutes) because it costs a bit of CPU time to perform the update. Note that during the first few seconds of rendering, the image refreshes much more often to give you a good quick preview (this behaviour is disabled when rendering animations). This value can be changed during a final render. If you change other settings during final render where this is possible, for example tonemapping or light groups, a film refresh will be forced automatically so you don't have to wait for the next scheduled film refresh.
LuxCore Error Log
Errors and warnings that happen during the preparation phase of a render are collected here. The error log is cleared before each render and before each viewport render. When the same error/warning is raised multiple times, it is only represented in one line, but with the number of times it was raised, e.g. "x13".
LuxCore Halt Conditions
The render properties contain a panel with the global halt conditions of a scene.
They allow to automatically stop the render process after a certain amount of time (in seconds) has passed, and/or after a certain amount of samples per pixel have been reached, or after the noise in the image falls under a certain threshold.
For animation renders, it is required to set at least one halt condition, either globally or for each render layer.
Note that render layers can override the global halt conditions. So you can for example have a foreground layer that is rendered with only 10 samples because it will get blurred in the compositor anyway, while your main render layer uses 1000 samples.
If you have more than one render layer in the scene it is also required to set at least one halt condition, because otherwise we could get "stuck" on one layer and never get to the next. This is because Blender cancels the render process entirely when you press the escape key, so we can't switch render layers here. In theory, BlendLuxCore could provide a button and/or shortcut for endless renders with multiple render layers, but this is probably not the most user friendly way.
TODO: Currently, halt conditions can't be changed while the render is running. It is planned to add support for this (update the wiki when it happens).