Image Space Incorporated released the 1.250 patch for rFactor, colloquially know as rFactor 1250. Part of the patch readme states "New MultiView option added for triple-head gaming only. Checking this option will use three viewports with standard FOV instead of one viewport with very wide FOV."
This option is labeled "MultiView" in the rFactor config utility, but the actual switch it makes in the config file is called "SubViews".
To enable this option, check the "MultiView" box in the rFactor config utility or open the Config.ini file in your rFactor root directory and change the "SubViews=0" line to "SubViews=2".
What ISI has done is designed a system that automatically takes a triplehead image, splits it into three sections, and gives each section its own field of view. This completely eliminates any image distortion on the side monitors, i.e. they look exactly like the center monitor. The (intended) side effect of this change is that the images on the side monitors can look like they're "angled out" from the center. The reason for this is because ISI has intentionally coded the MultiView option for a 3-monitor viewing system that wraps around the user. The only drawback that I've experienced is that my two side monitors, angled at 45 degrees, don't seem to be angled quite sharply enough to make the image entirely seemless. 45 degrees is already a fairly sharp angle through, requiring some major head-turning on the Windows desktop. My desk is constructed for triple monitors at 45 degree angles, so they can't really be turned any further, but even if they could I don't think I'd want to do it.
The images below are some screenshots using the Grand Prix Classics 1979 Formula One mod, on the starting grid at Watkins Glen, at 3072x768. Click the thumbnails for full-size images.
SubViews=0 (i.e. MultiView is OFF)
SubViews=2 (i.e. MultiView is ON)
Note the distortion-free side views, and also the fact that you can see more this way (instead of seeing back to the rear wing of the second car on the left, you can see all the way to the nose cone of the third car on the left). However, immediately apparent are the abrupt "kinks" in the view, as if someone folded the image outward at those points. These kinks are designed to match up with angled side monitors.
