Volumetric Fog uses an extremely optimized ray-marching algorithm to provide “volumetric sense” fog in front of your player. This great effect comes at a performance price that makes Volumetric Fog & Mist not suitable for mobile devices (at least mobile devices to date).
However, we have added a few optimization parameters to provide you with more control regarding the performance vs quality:
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Compute Depth: disable this option unless it’s required in your scene as this will add an additional rendering stage (it’s optimized but nevertheless it’s an additional hidden camera rendering stuff like billboard trees).
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Max Distance: reduce the max distance property to a value that matches your scene/requirements so no extra fog is calculated unnecessarily.
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Sky Haze: reduce to 0 to improve performance.
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Transparency Mode: set to None to avoid extra overhead.
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Downsampling: increase this value to improve performance. A high value will produce visible artifacts around objects. A x2 value usually works well. A x4 or higher value works better with elevated/cloud fog. You can enable the “Edge improvement” option to reduce fog bleeding/pixelization around geometry borders.
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Stepping: controls the step of the ray-marching algorithm. Reduce this value to improve performance.
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Stepping near: additional factor for the ray-marching step applied only to close distances. Increase to improve the fog effect when stepping is reduced.
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Distance (starting Distance in Fog Geometry group): reduce to 0 to improve performance.
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Height: try to set the minimum height for the look you need.
Optional features that you may check they’re either on (because you want them) or off (because you don’t want them and want to make sure they are really disabled):
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Point Lights: reduce the number of point lights that can illuminate the fog (Point Light section). Make sure the range for non-used slots is zero.
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Light Scattering: uncheck the Enable toggle to disable the effect and increase performance. Make sure that if you enable it, the effect is visible when facing towards Sun, otherwise you will be wasting lot GPU cycles!
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Fog Void / Fog of War: disable (either setting the fog void radius to zero) or disabling fog of war feature (toggle in its section) if you’re not using them to reduce GPU work.
