LOD_RADIUS under [TERRAIN] determines the size of the coverage area to be refreshed around the aircraft. It has a default value of 4.5.
However, a number of other aspects are also influenced by this value in addition to refreshing the coverage:
- visual quality – higher value = wider & clearer the coverage
- frame-rate – higher value = lower frame-rate
- stutter – higher value = more stutters
- memory usage – higher value = more memory consumed (higher risk to OOM crash)
- session load-up time – higher value = longer session load-up time
Nowadays, using a value higher than the default one is recommended as most video cards are equipped with 512MB or more memory.
Common values used range from 6 to 9. The best value for one’s system can only be achieved by trial and error; and different scenery set-up may encounter diverse results. For example, LOD_RADIUS in my various flying zones ranges from 5.5 to 8.
- Despite this setting, certain autogen objects still won’t appear until certain distance is reached or will disappear when the aircraft is away from the viewable range.
- Any changes made through SETTINGS inside FSX will revert the value of LOD_RADIUS in fsx.CFG to its default value (4.5). It needs to be changed again manually if required.