For a simple example, if I want to extend the distance that grass pops in, I've tried increasing the values found in the [Grass] section of the ini:
[Grass]iMinGrassSize=80bGrassPointLighting=0bDrawShaderGrass=1iGrassDensityEvalSize=2iMaxGrassTypesPerTexure=2fWaveOffsetRange=1.7500fGrassWindMagnitudeMax=125.0000fGrassWindMagnitudeMin=5.0000fTexturePctThreshold=0.0000fGrassMinStartFadeDistance=0.0fGrassMaxStartFadeDistance=70000.0fGrassDefaultStartFadeDistance=35000.0fGrassFadeRange=10000.0fGrassStartFadeDistance=70000
I've multiplied the fade values by 10. I have made these changes both in fallout_default.ini AND in falloutPrefs.ini, and I've been using the launcher so the changes in fallout_default.ini get propogated to fallout.ini
Nothing changes, though. The grass pops in/out at the exact same distance (I have a save that's sitting on the line where a patch of grass pops in and out). The grass is a simplified example of my problem; I ultimately want to increase the LOD of all objects, which have a tonne of settings in [LOD] that are not documented in the Fallout3 ini tweak guide. I was playing around with them as well, and noticed no changes no matter how much I changed the values.
As a side note, while looking up any precedent of this issue, I found a rumor that the Perception stat affects draw distance. I have personally tested this, and have found that Perception does not affect the draw distance of grass, objects, or terrain. My (untested) theory is that perhaps Perception affects the distance enemies show up on your compass, and people just got confused; that is an untested theory, however.