Published 23 May 2016
When designing for experiences in Virtual Reality a whole new set of design considerations comes into play than when designing for 2D screens. To help us to create experiences that doesn't frustrate or make users feel nauseous, the Google Cardboard team created these design principles to guide our work.
The principles are available via an Android app called Cardboard Design Lab which I highly recommend checking out to get the full picture. Needless to say, the app is best experienced via Google Cardboard.
Source: Designing for Virtual Reality
Without a visual aid it's hard to tell when objects are actually in the center of your view. Overlaying a visual aid or "reticle" makes targeting objects much easier. The best reticles are unobtrusive and react to interactive elements in the environment.
Many things affect text legibility. Font size, contrast, spacing, and more play a role. Virtual reality adds another factor: depth. About 3 meters from the viewer is a good distance for a comfortable UI. It's far enough away to be comfortably legible, but close enough to not interfere with most scenes.
VR can make people feel sick in some situations, such as during acceleration and deceleration. Good motion is smooth, with constant velocity.
It's easy to become disoriented in virtual environments. You should always include plenty of reference points so that the user can understand their surroundings.
The key to virtual reality is smooth, low-latency head tracking. No matter what, make sure at least one element in the scene always maintains head tracking.
Designing for VR means designing for 3D spaces. This creates a challenge of drawing the user's attention. A common technique in video game design is to leverage lighting cues. While subtle, users will be drawn to the brightest part of a scene.
Large differences in scale between user and environment are very effective in virtual reality. Use scale to affect how the user perceives their environment and their physical size in the world.
When triggering audio or other events, consider leveraging the user's position and field of view. It's an effective way to engage the user and immerse them in the environment.
In VR, you always know where the user is looking. The user's gaze can be utilized as a cursor to trigger passive interactions in the environment. This can help you reveal more information about the world.
Virtual reality is a carefully crafted illusion. The better your experience looks, the better the illusion. Take every opportunity to optimize the visuals of your world.