Comfort

Original article: Comfort

TL;DR

In mixed reality, monocular and binocular cues are vital for interpreting 3D space and depth. Devices like HoloLens require careful content placement and user movement considerations to avoid discomfort. Key terms, such as IPD and FPS, are essential for device calibration and optimal performance.

Bullet points

  1. đŸ‘ïž Monocular Cues: These are visual cues that only require one eye to interpret 3D shapes and relative positions of objects. Examples include linear perspective, which is the way parallel lines seem to converge as they recede into the distance, and occlusion, where closer objects block those that are farther away. These cues give our brains information about depth and distance even if we’re only using one eye.

  2. 👀 Binocular Cues: These cues require both eyes to understand depth and relative positions of objects. For instance, binocular disparity refers to the slight difference between the two visual images (one from each eye) that allows for depth perception. Vergence is the simultaneous movement of both eyes to maintain binocular vision.

  3. 🎼 Vergence-Accommodation Conflict: In natural viewing, our eyes’ focus (accommodation) and their rotation (vergence) are linked. However, in many head-mounted displays, this link is broken, leading to visual discomfort or fatigue. This conflict arises when our eyes try to focus on a virtual object at one distance while converging at another.

  4. đŸ•¶ïž HoloLens Displays: The HoloLens is a mixed reality device with its display fixed at an optical distance of 2.0m. This means users must always focus at this distance for a clear image. To reduce visual discomfort, it’s recommended to place most content near this distance.

  5. 📏 Optimal Hologram Distance: For the best user experience on HoloLens, holograms should be placed between 1.25m and 5m from the user. Placing holograms too close (under 40cm) can cause discomfort due to the vergence-accommodation conflict.

  6. đŸš¶ User Locomotion: This refers to how users move within a virtual environment. If the virtual movement doesn’t match the user’s physical movement, it can lead to motion sickness. It’s crucial to design experiences that align virtual and physical movements as closely as possible.

  7. 📊 HUDs (Heads-Up Displays): In video games, HUDs provide vital information directly on the screen. In mixed reality, a HUD that’s fixed to the user’s head orientation can cause discomfort. Instead, it’s better to have HUDs that move with the body, reorienting only after significant head rotation.

  8. 📜 Text Legibility: Text in mixed reality should be easily readable. This involves considering the display’s properties, such as pixel density and brightness, as well as the text’s properties, like font size and weight. Proper legibility ensures users don’t strain their eyes.

  9. đŸ–Œïž Holographic Frame: This refers to the user’s field of view in a mixed reality experience. Designers should consider how much users have to move their heads to interact with content. Excessive or unnatural movements can lead to discomfort.

  10. đŸ’Ș Arm Positions: Continuous hand gestures or repeated air taps can lead to muscle fatigue. Mixed reality experiences should be designed to minimize these repetitive actions. For instance, voice commands can be integrated to reduce the need for hand gestures.

Keywords

  • Monocular Cues: Visual cues that only require one eye to interpret 3D shapes and relative positions of objects.

  • Binocular Cues: Visual cues that require both eyes to understand depth and relative positions of objects.

  • Vergence: The relative rotations of the eyes required to focus on an object.

  • Accommodation: The adjustment of the eyes’ focus to the distance of an object.

  • Vergence-Accommodation Conflict: A phenomenon where the eyes’ focus and rotation don’t match, leading to visual discomfort.

  • HUD (Heads-Up Display): A transparent display that presents data without requiring the user to look away from their usual viewpoint.

  • Locomotion: The ability to move from one place to another.

  • IPD (Interpupillary Distance): The distance between the pupils of an individual’s eyes.

  • VO (Vertical Offset): The potential vertical offset of digital content shown to each eye relative to the horizontal axis of the viewer’s eyes.

  • FPS (Frames Per Second): A measure of how many individual frames are displayed in one second of video or animation.