Carter Bray

@Paul, @Jeff, I didn't mean to suggest that you could prevent motion sickness just by adjusting field-of-view or viewing distance, or that there aren't problems that are unique to Minecraft that cause motion sickness; only that the distortion itself is not a bug and is not unique to Minecraft. @Paul I can't answer your question of what field-of-view to use for Minecraft to get the same experience you get in Skyrim because there are a lot of things that can cause motion sickness.

I'm not sure why you don't believe that Skyrim has the same behavior. I've taken a couple of screenshots from a Skyrim video showing the same effect. (Note that the title of the video is "Skyrim Realistic Sun mod" but the screenshots were taken from the "Standard sun" section of the video). You can see that the moon is no longer circular when it's rendered on the edge of the screen due to linear perspective. I've outlined it with an ellipsoid but the actual shape is more egg-shaped since the amount of stretching increases across the shape.

Along the lines of what @Jeff was saying, it could just be that the blocky art style makes the effect more pronounced in Minecraft compared to other games like Quake or Skyrim.

There seems to be a lot of confusion about what this distortion is and whether it is expected or unique to Minecraft. The stretching at the sides of the screen is an expected result of linear perspective which is used by virtually all hardware accelerated graphics engines. The way this works is that the 3D scene within the field of view is projected onto a flat rectangle, this flat rectangle is then displayed on your screen. In ideal viewing conditions there will be no apparent distortion since the rays from the viewer to the display and from the projected scene to the scene will be parallel. There are few important things to note:

• The apparent size of an object is not necessarily the same as its physical size on screen (i.e. width in pixels) due to perspective. In other words, the pixels towards the edge of the screen appear relatively smaller than pixels in the center of the screen, so objects need to be physically larger (in pixels) to appear to be consistently sized on screen.

• The amount of stretching depends on the field of view. The larger the field of view, or equivalently, the closer you are to your display, the more stretching needs to occur at the edges to keep the physical size and apparent size consistent across the entire screen.

• If the field of view used by the rendering engine does not match your field of view to the display then you will see distortion since the physical size and apparent size will not be consistent across the entire screen. People can typically tolerate some slight discrepancies without an issue, but if you look for the distortion it will become hard to ignore as others have pointed out above.

If you are seeing stretching at the edges of your screen in normal viewing conditions then you should decrease the field-of-view in game and/or move closer to the screen. If you are seeing pinching at the edges of your screen in normal viewing conditions then you should increase the field-of-view and/or move further from the screen.

The video linked in the description is using 70 degree vertical field of view and a 48:9 aspect ratio which gives a horizontal field of view of 150 degrees. If you're watching this video fullscreen on a 24-inch 16:9 monitor then the optimal viewing distance is 5.6 inches from the screen. (Typical viewing distances are 20-40 inches). You can see the same distortion in Quake 4 in this video, or Skyrim in this video.

Motion sickness can be caused by a lot of things, including misaligned field of view. However, the distortion at the edges of the screen described in this issue is not a defect, it is required for perspective-correct rendering.