17. Lesson Review

In this lesson we learned…

What is simulator sickness?

Simulator sickness is a type of motion sickness induced by motion in VR. It stems from a disconnect between what your eyes are seeing and what your body is feeling. Not everyone is affected by sim sickness in the same ways. We can’t rely on our users to get used to it. Instead, they should be taking off the headset and wait until the sickness fades.

What ways can we avoid simulator sickness from affecting our users?

• Use constant velocity when moving.
• Use movement mechanics where users are looking forwards.
• Use movement sparingly in our experiences.
• Give users control over when and how frequently they move.
• Keep movement time short.
• Keep a solid high framerate.

What is the difference between dash and teleport movement mechanics?

Teleport movement involves very little time between when users indicate they want to move and when they actually move. Users will essentially click and then show up in the new spot. Usually this movement mechanic has a quick fade to black and then fade in again to signify the move.

Dash involves letting the users experience a brief period of movement, simulating running forward to their destination.

Both methods are generally paired with some of the movement systems mentioned below.

What is ground raycasting? What are the benefits of using it?

Ground raycasting is doing a raycast to detect when the user is looking at the ground and then using that as a point to move to. This movement mechanic gives users a lot of control over where they can go in the scene. It also ensures that users are looking in the direction they want to move to.

Note: Because users can move anywhere they want, be sure to consider what they can see from any area in your scene.

What are waypoints? What are the benefits of using it?

Waypoints allow users to go to specific areas in the scene. They aren’t as free to move around as in the ground raycasting, but that means that we can take some shortcuts when creating our environment.

What is meant by “on rails” movement?

In “on rails” movement, the user moves at a constant speed without stopping. This can cause sim sickness if users are trying to look in directions other than in the direction they are moving.

What is iTween?

iTween is an animation and scripting plugin available on the Unity asset store. It will help us move between two points easier than writing all of the code ourselves.

We will be using iTween’s MoveTo for moving between two points. The code example below, is how we’d move our object (likely a player camera rig) to another position (positionB) over a time period of 5 seconds. Keeping the ease type set to linear will ensure a constant speed to reduce the chance of sim sickness.

iTween.MoveTo(objectToMove,
     iTween.Hash(
          “position”, positionB,
          “time”, 5,
          “easetype”, “Linear”
     )
);

What should be included in our project documentation?

You’ll likely have some sketches, screenshots, notes from user testing, and maybe a video of you conducting a user test. Anything that can be used to get feedback can be used to document your VR creation process.