Elder Scrolls IV: Oblivion Tweak Guide
[Page 10] Advanced Tweaking (Pt.3)
[Tree & Grass Variables]
iMinGrassSize=120 - This setting controls the density of grass clumps. The higher the value, the less tightly packed grassy areas will be, resulting in more empty spaces in grassland, and thus noticeably higher FPS in heavily grassed areas. I suggest a value of 120 to improve FPS without overly thinning out grass.
Update: You can also use this Low Poly Grass Mod to reduce the polygon count (complexity) of grass, boosting FPS further.
The above settings control the distance at which grass ends, and the distance shortly before that which it starts to fade away. You can lower these values to increase performance, and also by reducing the difference between the FadeDistance and EndDistance.
bGrassPointLighting=0 - Setting to 1 provides more accurate lighting on grass at the cost of reduced FPS.
bDrawShaderGrass=1 - If set to 0 removes all grass which obviously improves FPS in such areas at the cost of realism.
iTreeClonesAllowed=0 - If set to a particular value, appears to determine in part the number of possible tree clones (copies of the same basic tree type) which are generated. The higher the value, the greater the potential to improve FPS and stuttering by reducing texture types and processing time, however I have not seen a major performance or visual difference from various values of this setting.
iCanopyShadowScale=512 - This value determines the appearance of tree shadow textures - lowering the resolution value (in multiples of 8) will make the tree shadows appear finer and more detailed, but this will also introduce a visible tiling pattern to the shadows. See an animated screenshot comparison by clicking this link: Obl_CanopyShadowScale.gif (768KB). Altering this value doesn't appear to have a significant impact on FPS, but may do on older graphics cards.
bEnableTrees=1 - If set to 0, turns off all trees, boosting FPS but making things highly unrealistic outdoors.
bForceFullLOD=0 - If set to 1 uses full Level of Detail (LOD) for trees, making them appear slightly better at the cost of a small FPS drop.
The above settings control the additional reflections possible on the surface of water areas. When set to 1, they allow nearby trees, objects, and other characters to reflect in the water. Note that this reduces FPS in busy areas, and that the additional reflections are only visible when you and the objects are closer to the water.
uDepthRange=125 - This option controls the depth of water visibility from above. The higher the value, the clearer the water appears, however some water glitches may also start becoming apparent, and FPS may be reduced as well.
bUseWaterDepth=1 - If set to 0, water becomes completely opaque (i.e. you cannot see into it at all from above). This can resolve some of the visual glitches which result from changing the uGridsToLoad value, and can also improve FPS, at the cost of some realism.
uNumDepthGrids=3 - Also appears to control the depth of water visible, with lower values making water less transparent. If set too high this results in glitches, but if set to 1 can resolve issues with the uGridsToLoad value being higher than 5 and improve FPS as well.
bUseWaterLOD=1 - If set to 0 removes all water.
fSurfaceTileSize=2048.0000 - Controls the size of the water texture grids. The smaller this value, the smaller the size of texture tiles, and the faster and more tightly packed the water ripples will appear.
bUseEyeEnvMapping=1 - If set to 0, disables environment mapping on character eyes. This makes eyes look slightly less natural and not influenced by the character's surroundings, but can improve FPS slightly.
bDisableHeadTracking=0 - If set to 1, stops characters' heads swiveling to track other characters, including your own (when in 3rd person view). Does not seem to influence performance much, and is not recommended.
bFaceGenTexturing=1 - If set to 0, Face Generator textures are removed from faces - this means they will all look smooth and lack things like age lines. There will be a slight performance improvement by doing this.
bFaceMipMaps=1 - If set to 0, character faces are slightly less detailed but FPS may improve slightly.
SMainMenuMovieIntro=Oblivion iv logo.bik
SIntroSequence=bethesda softworks HD720p.bik,2k games.bik,game studios.bik,Oblivion Legal.bik
The above two settings control the bulk of the introductory movies which are loaded up each time you start Oblivion. By setting each of these options to blank (e.g. SMainMenuMovieIntro=), you will prevent the intro movies from starting up, thus getting to the main menu quicker, reducing memory usage as well.
SMainMenuMovie=Map loop.bik - This is optional, but for those who also want to disable the animated map in the background of the main menu, set this option to = blank as well. This can also improve mouse responsiveness in the main menu.
fDlgFocus=2.1000 - This setting determines the level of camera zoom on people's faces when you enter into conversation with them. A value of 4.0000 is equivalent to no zoom at all, while something like 3.0000 gives a mild zoom which I feel is better than the extreme level of zoom provided by the current setting.
bHealthBarShowing=0 - If set to 1, shows a small yellow health bar above an enemy in combat, rather than the normal curved health bar in the center of the screen.
The above settings determine the 'safe zone' for the placement of your Heads Up Display (HUD). By reducing the values, such as to a value of 5, this will move the HUD elements at the bottom of the screen even lower, making them less intrusive.
[HDR & Bloom Variables]
The above sections in the .ini file relate to HDR lighting effect parameters (the first two being interior and exterior HDR lighting), and the third being Bloom lighting parameters. You can alter these values in an attempt to make the lighting effects better suit your tastes. For example, some people suggest that using the following settings for the Bloom (BlurShader) lighting makes it look more 'HDR-like' without the same performance impact as real HDR:
Obviously you will have to experiment or find someone who has values which you may find desirable, but note that varying these can result in strange visual glitches in certain areas, such as an oversaturated sky or odd water colors.
That covers the list of useful .ini variables I have found. Remember that I have tested all of the .ini settings, however if you know of any more .ini tweaks not listed above which actually do something useful, and you have tested them properly, please Email Me and I will consider including them. Note that some of the popular tweaks doing the rounds do not work as people believe. People often take a wild guess at what an option in the .ini file does and then neglect to test the tweak under a consistent reproducible environment. Certain tweaks are sometimes credited with fantastic properties which are virtually impossible based on what they actually can do. So please, while I would love to hear more about working tweaks, including any corrections to the list above, make sure you have tested the tweak out properly and have a good idea of what it does.
'Pre-Tweaked' .ini File
The most common request from people playing Oblivion is for a 'pre-tweaked' .ini file which contains all the optimizations required to make the game run well. No doubt people are wanting the same thing from this guide. My answer is that unfortunately no such thing is possible. Using other peoples' .ini files will only lead to instability (i.e. crashes) and/or graphical anomalies, since many of the entries are designed specifically for each system's capabilities, and can't just be swapped with others unless they have an almost identical system, and similar visual quality vs. performance preferences.
I recommend that you use the listing above to wisely administer only a few tweaks at a time in your Oblivion.ini file, testing them out to see how they perform on your system. I have provided my recommendation where I feel a tweak can generally be applied to most systems. I strongly advise against using other peoples' .ini files, but in the end it is obviously up to you. As with all my other guides, I can only point out that there is no 'one size fits all' .ini file, as many of the choices are up to peoples' tastes as to the performance vs. visual quality trade off, as well as your graphics card's hardware capabilities.
The next section covers a range of very important performance tips, tweaks and advice which should not be skipped.