Sadly, setting cl_mouseAccel to "0" doesn't turn off mouse acceleration in QuakeLive on OS X unless you use a third-party mouse driver to disable OS X's mouse acceleration. And setting in_mouse to "2" doesn't work either; OS X's mouse acceleration is still active in QuakeLive. Either in_mouse "2" is not implemented properly and completely in QuakeLive for OS X or it is unable to override the system settings.
With OS X's system-wide mouse acceleration disabled, then QuakeLive's cl_mouseAccel and in_mouse settings work as they do in Windows.
Third-Pary Mouse Drivers that allow you to disable OS X's mouse acceleration
- SmoothMouse allows you to disable acceleration or set it to match Windows acceleration curve. Also, eliminates the mouse lag that affects OS X.
- Notch setting "4" = Windows mouse setting "6". Acceleration OFF + notch "4” = 1:1 mouse setting.
CursorSense [$9.99 USD]
- From the same developer as SteerMouse. Allows you to adjust or disable acceleration and sensitivity. You can also create multiple presets for different devices and apps.
SteerMouse [$20 USD]
- Well designed mouse driver and direct competitor to USB Overdrive. Can be used in conjunction with CursorSense.
USB Overdrive [$20 USD]
- Respected Mac device driver that's been around for a long time. I used to use this but I've grown unhappy with the unfixed bugs and long, long times between updates. Still, it's a great third-party mouse driver.
ControllerMate [$24.95 USD]
- Gives you insanely detailed control over any input device you might have. I think it's overkill if you just want to disable mouse acceleration but if you love to fine-tune things and create your own custom acceleration curves, then you'll probably like this.
SmoothCursor [$2.75 USD]
- Nicely designed app and inexpensive but will not completely disable OS X's mouse acceleration curve so it's not 1:1 linear. From the developer:OS X lets you set a 'tracking speed' (or acceleration) range of 0 up to 3, where 0 translates to 'no acceleration'. SC supports a broader range: -6 up to 6, where 0, again, translates to 'no acceleration'. Negative ranges cause acceleration to work in inverse mode (the more the mouse accelerates, the slower the cursor moves, and viceversa), etc. The acceleration curves used by SC are in fact the ones provided by Apple. And yes, they are far from linear.