From CarbonFire of the PA forums:

[SIZE="4"]CARBONFIRE'S Mouse Smoothing and Turret Speed Fix for BFBC2[/SIZE]

This fix will change the way your mouse works in-game for both your regular infantry view and when using stationary / vehicle turrets or Choppers.

Currently Battlefield Bad Company 2 has mouse smoothing on by default, with no way of turning the feature off in the game's settings. Mouse Smoothing normalizes your mouse's input, "smoothing out" very fast or very slow movements. The result of this smoothing is often aiming that feels floaty or laggy, which is obviously not desirable in an FPS!

Also BFBC2 turrets tend to turn at a much slower rate compared to normal infantry mouse aiming. This fix will solve that problem and opens the potential for turrets to reach their maximum turning speed without affecting infantry movement. This will also make vehicle turrets turn faster, but they have a hard-coded maximum turning speed, so don't expect to pull a quick 180 with a tank turret anytime soon.

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DISCLAIMER: This fix involves changing values within key game files that are relied upon to properly run BFBC2. It is advised that you back up these files prior to editing, and that you don't go changing any values outside the ones shown below. Use this fix at your own risk, you assume all responsibility if you mess up your game.
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Ok, with that out of the way, here are the steps to killing mouse smoothing and fixing those slow turrets:

Go to your My Documents > BFBC2 folder. We will be making changes to the Gamesettings.ini file, as well as the files within the <input> folder, so go ahead and make back-up copies of those first.

[*]Make sure BFBC2 is closed
[*]Open GameSettings.ini and make the following changes:

Sensitivity0=0.000000
Sensitivity1=0.000000
Sensitivity2=0.000000
.
.
.
Scheme0Sensitivity=2.50000 <--- This value will be your normal in-game mouse sensitivity, it seems to have no effect on turrets or vehicles. Feel free to experiment with this value and change as necessary. I found 2.5 to be a good compromise between fast turning speed and precision with a 1000DPI mouse, but YMMV. Values from 0.001 to 500+ are valid.
.
.
InputAcceleration=0


[*]Save and close GameSettings.ini

[*]Navigate to the <input> folder, open infantry.dbx using notepad

[*]Search for the following line:
<field name="ConceptIdentifier">ConceptPitch</field>

[*]Below this line you'll see several similar-looking blocks of data. Make the following changes:



[*]Just Below this section you'll find a similar section with the following header:
<field name="ConceptIdentifier">ConceptYaw</field>

Repeat Step #6 here, changing the "NormalizeInput" values to false.

[*]Save and close infantry.dbx

Mouse Smoothing should be effectively disabled at this point. However this change will render turrets and vehicles nearly impossible to use, so make sure you follow the remaining steps...
.
[*]In the <input> folder, open land.dbx using notepad
[*]Search for the following line:
<field name="ConceptIdentifier">ConceptPitch</field>

[*]Again, you'll see several similar-looking blocks of data below this section. Make the following changes:



Note: 10 here is a suggestion, again feel free to experiment. Values below 5 seemed too sluggish for my taste, while values far greater than 20 did not seem to make turrets any faster at turning, just more "squirrely" (changing directions more quickly, making it harder to stay on target).
.
[*]Just Below this section you'll find a similar section with the following header:
<field name="ConceptIdentifier">ConceptRoll</field>

Repeat Step #11 here, changing the "NormalizeInput" values to false, and changing the ScaleValue to your desired value.
[*]Save and close land.dbx

Note: The next section applies only to piloting Helicopters (not including the UAV). Gunner seats and the UAV seem to follow the "land" control guidelines for turning speed. Also this fix was only tested for mouse flight. If you fly with a joystick or keyboard-only controls, you'll probably have to play with these settings a bit more to get them to work with your setup. Good Luck!
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[*]In the <input> folder, open air.dbx using notepad
[*]Same as before, search for the following line:
<field name="ConceptIdentifier">ConceptPitch</field>

[*]Find the ScaleValue field for the mouse input and change it to 200
(NormalizeInput should already be false for air vehicles, but if it isn't, make sure it's set to false).

[*]Search for the following line:
<field name="ConceptIdentifier">ConceptRoll</field>

Find the ScaleValue field and change it to 200

Choppers seem to need much higher values to compensate for setting the "main" mouse sensitivity to zero in step 2. Much lower than 100 and the chopper is hard to move. I tried up to 300, and while it worked, it wasn't a significant change. Again, experiment and find a value that suits you. Like turrets, there is a hard-coded maximum turning speed that the game allows, so don't expect this to transform your chopper into a super stunt machine.
.
[*]Save and close air.dbx
[*]Start up BFBC2
[*]ENJOY!
[*](optional)Curse EA as the servers go down again and go play single-player instead

One final note: Vehicles / Turrets will always be affected by some smoothing, as there is no Scheme#Sensitivity or other setting I was able to find in GameSettings.ini that changed vehicle/turret behavior.

Hope this tutorial makes your BC2 experience just a little more awesome.

See you on the Battlefield soldier 8-)

Fixed the formatting a little
edit: also if you don't have the input folder, it's because you are still using all the default keybinds. Just change a single bind (e.g. alltalk to y) and the folder should be created

SO which values should I change if I just want to adjust sniper scope and tank speed?

battlefield.Spunkify wrote:SO which values should I change if I just want to adjust sniper scope and tank speed?

From what I can tell you may not be able to do one without the other, but you can just try everything beneath:

Mouse Smoothing should be effectively disabled at this point. However this change will render turrets and vehicles nearly impossible to use, so make sure you follow the remaining steps...

and see if that works

Bump, great post anyone who doesn't think this will help them is crazy

Awesome man! Thanks a bunch. Is it PB safe?

any chance you can copy and paste those sections into this forum, inside tank works great now, trouble is when im on foot now i cant turn, tryed this twice now, with no affect
regards
josh

battlefield.Doc_uk wrote:any chance you can copy and paste those sections into this forum, inside tank works great now, trouble is when im on foot now i cant turn, tryed this twice now, with no affect
regards
josh

Wait so you did this and now you cant turn?

battlefield.Spunkify wrote:

battlefield.Doc_uk wrote:any chance you can copy and paste those sections into this forum, inside tank works great now, trouble is when im on foot now i cant turn, tryed this twice now, with no affect
regards
josh

Wait so you did this and now you cant turn?

he did and messed up somewhere but didn't make a backup copy of the files he modded. Works fine for me. I feel like I'm actually playing a PC fps now.

I'm using Scheme0Sensitivity=1.000 @ 800 DPI instead of 2.5 works really nice for sniping with with pistols and smgs

so why cant one of you copy and paste the sections i need?
regards
josh

battlefield.Doc_uk wrote:so why cant one of you copy and paste the sections i need?
regards
josh

you need the infantry part right? well It may not work.

If I get it to work tonight I will make a tutorial vid for it.

battlefield.Doc_uk wrote:any chance you can copy and paste those sections into this forum, inside tank works great now, trouble is when im on foot now i cant turn, tryed this twice now, with no affect
regards
josh

It sounds like you may not have adjusted both pitch and yaw

cheers 3up, can ya copy paste this one now
land.dbx
i need both
regards
josh

It might just be easier host the files somewhere, not to mention it would keep from uselessly cluttering up the thread.