Fallout 3 Tweak Guide
[Page 9] Advanced Tweaking (Pt.2)
The above two values determine the screen width and height in pixels respectively - you can specify a custom screen resolution by changing these values, though it may only work in Windowed mode (FalloutPrefs.ini).
The above variables are useful particularly for those with older monitors. They are the same as the in-game Brightness slider, however here you can adjust both the overall brightness level with fGamma as well as altering the upper and lower limits allowed, in case you need to adjust Brightness beyond the limits allowed in the game (FalloutPrefs.ini).
iShadowMapResolution=1024 - This variable determines the resolution of the shadow maps used in the game, and is the same as the Shadow Quality Launcher setting (See In-Game Settings section). The preset values as assigned by the Launcher are =1024 for High, =512 for Medium and =256 for Low. However here you can assign a custom value (always using a multiple of 8), to further adjust the quality of shadows in the game. For example try a value of =2048 to further improve shadow quality above High, or a value of =128 to reduce shadow quality below Low to gain extra FPS (FalloutPrefs.ini).
bUseRefractionShader=1 - This setting controls the shimmery/invisibility effect sometimes used in the game. Setting it to =0 can noticeably boost FPS in areas where this effect is used, such as around invisible characters (e.g. when using the Stealth Boy), or when firing weapons which give off a heat haze (e.g. missile explosions). However obviously this can also ruin realism and prevent appropriate special effects (Fallout.ini).
bDoSpecularPass=1 - If set to =0, removes the shiny effect on most surfaces. While you can adjust the level of shine to some degree using the Specularity Fade in-game setting (See In-Game Settings section), this variable is very useful for those who think the game world is too shiny on the whole; by disabling this option you can change the appearance of the game world by removing the shine, and also noticeably improve FPS on many systems (Fallout.ini).
iMaxDecalsPerFrame=10 - This value determines the maximum number of decals (mainly blood splatters on the ground) visible on screen at any time. It is the same as the 'Decal Cap' Launcher setting (See In-Game Settings section). However here you can assign values above or below the normal 2 - 10 scale allowed by the Launcher options slider. For example you can set it to =0 to disable all blood splatters on the ground, or raise it above 10 to make things much more messy. Note that decals can have an impact on performance, so raising this value can reduce FPS during combat (FalloutPrefs.ini).
fDecalLOD2=1500.0000 - In my testing, many of the decal-related settings seem to have no impact at all on decals (blood splatters and bullet impact holes), whether it be on their size, frequency, life time, etc. However this variables does have a very noticeable impact on decals. The lower the value for this setting, there will effectively be less decals shown. For example if you set it to =0, no blood splatters, bullet holes or scorch marks will be generated when firing your weapons. This can improve FPS during heavy combat for some people, but is obviously unrealistic (FalloutPrefs.ini).
uMaxDecals=100 - This variable seems to determine how many decals will remain on screen for longer than a few seconds. It won't prevent multiple decals from being shown, but if you lower the number, additional decals above the value you set for this variable will fade out very quickly (FalloutPrefs.ini).
uGridsToLoad=5 - Increasing the uGridsToLoad value (always in odd steps of 5,7,9,11 etc.) will increase the number of grids around the character in which full texture and object data will be loaded up and visible as they wander around. This improves overall visual quality by increasing graphical detail on more distant game world elements. Indeed certain objects and structures which were otherwise not visible before will now be visible. The higher the value, the more you will see of the game world in return for a sharp drop in framerate, and noticeably longer loading times. There may even be more prominent stuttering as well, not to mention the possibility of visual glitches and the greater likelihood of crashes due to the extra memory usage. Unlike Oblivion, in my testing using a value of =11 I didn't see any visual glitches in Fallout 3 at all, however my performance fell by more than half, and I eventually experienced a crash to desktop. As you increase the uGridsToLoad value, you may want to also increase the uExterior Cell Buffer value to accommodate the greater cell data and prevent crashes and stuttering. Note: It appears that if you save a game with a higher value for this variable, you cannot then lower the value again as your saved game will no longer load properly. So on balance the default value of 5 for uGridstoLoad is a good compromise between visual detail, performance and loading pauses, though high-end machines can try higher values, but make sure your system can handle it in a range of areas before committing to it by saving your game (Fallout.ini).
These two variables are actually quite important for overall Level of Detail. They correspond to the Object LOD Fade and Tree LOD Fade settings available in the Launcher options and are covered in the In-Game Settings section. In effect they determine the visible distance for buildings and trees respectively. In the Launcher they're restricted as to how high you can raise them, however here you can raise them to very high values (e.g. to =500000) and thus increase the number of buildings, objects and trees visible in the distance. Furthermore the performance impact seems minimal at best, and certainly is nowhere near as high as the uGridsToLoad variable which does something similar (FalloutPrefs.ini).
fSplitDistanceMult=1.5 - This variable is the same as the Land Quality Launcher option (See In-Game Settings section). However while the Launcher slider only goes up to a value of 1.5, by raising it further here (e.g. to a value of =10), you will get a more noticeable increase in the level of detail in distant landscapes, although FPS will similarly be reduced by a noticeable amount (FalloutPrefs.ini).
These two variables effectively control how large the Sun appears to be in the sky, and how much glare it has. Lowering the values lowers the size of the Sun, raising them makes it bigger (Fallout.ini)
bAllow30Shaders=0 - If set to 1, this option will allow (but not force) the use of Shader Model 3.0 on graphics cards which support it, namely Nvidia GeForce 6600 or newer, or ATI X1000 series or newer. This can potentially improve performance when using HDR rendering for example. However to force the actual use of 3.0 Shaders after making the above change, you will also need to check your RenderInfo.txt file, found under the same directory as your .ini files, and near the bottom the file check which shader package it uses (e.g. Shader Package : 13). Then go to the \\Program Files\Bethesda Softworks\Fallout 3\Data\Shaders\ folder and rename that particular package to something else (e.g. rename shaderpackage013.sdp to shaderpackage013._bak. Now copy shaderpackage019.sdp and paste it back into the same directory, and rename this new copy to the package name your card uses (e.g. rename it to shaderpackage013.sdp in this example). This will supposedly force Fallout 3 to use the Shader Model 3.0 shaders in the game. In practice this doesn't appear to noticeably alter image quality or performance, so at best it might be used for troubleshooting purposes (Fallout.ini).
The above two options allow you to raise the maximum number of Interior and Exterior Shadows possible. Normally you can adjust these using the Max Interior Shadows and Max Exterior Shadows options in the Launcher (See In-Game Settings section), however here you can set them beyond their normal maximum of 6 if you wish (FalloutPrefs.ini).
The variables above can all be adjusted under the View Distance tab of the Fallout 3 Launcher options. From top to bottom above, they relate to: Actor Fade, Object Fade, Specularity Fade, Light Fade, Item Fade and Shadow Fade respectively, and are all covered in more detail in the In-Game Settings section. However here you can adjust them beyond the maximums allowed by the Launcher sliders (FalloutPrefs.ini).
The next page continues the .ini tweaks.