From LuxRender Wiki
The refine brush is a tool that lets the user define which areas of the image LuxRender should focus on. This can be useful in situations where after some time of rendering, a particular area contains considerably more noise than the rest of the image.
This tool works by drawing an overlay over the rendered image, on which one can indicate areas that LuxRender should focus on. After drawing those areas and pressing the Apply button, LuxRender will dedicate a larger part of its calculations to these areas.
There are two drawing tools:
- the Add Importance Pen is used to indicate areas that need to be focused on
- the Subtract Importance Pen can be used to remove (or partially remove) areas that have been drawn with the Add Importance Pen
The cursor icon contains a plus sign when using the Add Importance Pen and a minus sign when using the Subtract Importance Pen.
This slider controls the size of the pens.
This slider controls the strength of the pen strokes.
This slider controls the visual appearance of the Refine Brush drawing overlay. This does not have any effect on the effect of the Refine Brush functionality itself.
Removes all Refine Brush markings.
Removes the most recent brush strokes.
Pressing the Apply button will make LuxRender use the currently visible Refine Brush areas.