HTC Vive Teleportation System with Parabolic Pointer

This is an easy-to-use teleportation system for the HTC Vive and the Unity game engine. The system is modelled after Valve's game for the Vive The Lab, where the player can traverse VR environments that are bigger than the play area. Below you can see myself demoing the system (click for higher quality):

The system presented here solves a number of problems:

1. Calculating Navigable Space: You obviously don't want the player to be able to teleport out of bounds, or inside opaque objects. To solve this problem, my system uses Unity's generated Navigation Mesh as the boundaries that the player can teleport to. Because this process is piggybacking Unity's work, it is stable and can be used reliably in most projects. In order to preload this data, simply add a "Vive Nav Mesh" component anywhere in your scene, and click the "Update Navmesh Data" button in the inspector. You can of course update the Vive Nav Mesh component with new NavMesh bakes whenever you update the scene. The above process is illustrated below:

   

2. Selecting a Teleport Destination: This system uses an intuitive parabolic curve selection mechanism using simple kinematic equations. Once again, this was inspired by Valve's The Lab. As the user raises their controller to a higher angle, the selection point grows farther away. If the user raises the remote past 45 degrees (maximum distance of a parabolic curve) the angle stays locked at that distance.

3. Representing the Play Area: It is often useful to know where the chaperone boundaries will be after teleporting. For this reason the system draws a box around where the chaperone bounds will be.

4. Reducing Discomfort: The screen fades in and fades out upon teleportation (the display "blinks"), reducing fatigue and nausea for the user.

Provided in this Unity project (version 5.3.4p6) are two sample scenes: one is integrated directly with SteamVR and one may be used to demo the system if you don't own or have access to an HTC Vive. The source code is well documented and commented and may be used following the MIT Licence (see LICENSE.txt).

Getting Started

To get a basic teleportation setup running you need to use three components:

• The Vive Nav Mesh component handles the conversion between Unity's NavMesh system to a renderable mesh. It also calculates the borders of the NavMesh so that they can be shown to the player when choosing a place to teleport.
• The Parabolic Pointer component generates/displays a pointer mesh and samples points from a Vive Nav Mesh.
• The Vive Teleporter component handles the actual teleportation mechanic. It pulls pointer data from a Parabolic Pointer so that it knows where to teleport. It also smoothly fades the screen in and out to prevent discomfort when the player decides to teleport. It also interfaces with SteamVR to handle button press events, controller management, haptic feedback, and displaying the room boundaries when choosing a place to teleport.

Quick Note: The Teleport Vive and Parabolic Pointer components both automatically add a Border Renderer component. Border Renderer simply generates and renders a mesh to display the borders of the Vive Nav Mesh and the SteamVR play area.

Step 1: Configure the Vive Nav Mesh

Start by adding a Vive Nav Mesh object. You can find a preconfigured Vive Nav Mesh at the path: Vive-Teleporter/Prefabs/Navmesh.prefab in your Assets folder. You can put this object anywhere in your scene's heirarchy and at any position in the scene.

Next you need to bake a Navigation mesh ("Navmesh") in Unity. This can be done in the Navigation window (Window > Navigation).

Here are a few more considerations to keep in mind:

• The system automatically culls sloped navmesh triangles. This means that any parts of the navigation mesh that aren't facing directly upwards are disregarded by the teleportation system. This makes sense in VR, because the player can't actually walk up slopes!
• You must use physics colliders on all teleportable surfaces. The parabolic pointer (see step 2 below) uses physics raycasts to determine where the player is pointing. Because of this all teleportable surfaces must have a collider (as well as surfaces like walls that aren't teleportable but block the pointer anyway).
• It might also be a good idea to assign different Navigation Areas to areas that are not teleportable. This is helpful for optimization reasons (so that the system doesn't need to render an enormous preview mesh when the player chooses where to teleport) and for game balance reasons (so that the player can't teleport outside of the map).

After you have baked the Navmesh (using the "Bake" button at the bottom of the Navigation window) go back to the Vive Nav Mesh object you created earlier. If you have decided to assign specialized Navigation Areas (see above) you can choose which areas are teleportable with the Area Mask property. Then, click on the "Update Navmesh Data" button in the inspector and you should see your Navigation mesh display in the Scene View.

Step 2: Configure the Parabolic Pointer

Next add a Parabolic Pointer object. You can find a preconfigured Pointer at the path: Vive-Teleporter/Prefabs/Pointer.prefab in your Assets folder. You can put this object anywhere in your scene's heirarchy and at any position in the scene.

You can of course tweak any of the settings in the Parabolic Pointer script, but you only have to set one of them: assign the Vive Nav Mesh object from Step 1 to the "Nav Mesh" property of the Pointer.

Step 3: Configure the Vive Teleporter

Lastly you need to add a Vive Teleporter Component (Component > Vive Teleporter > Vive Teleporter) to the SteamVR Camera. This is the camera that is used to render to the Vive's display. If you are using the [CameraRig] prefab from the SteamVR Unity plugin you should add the Vive Teleporter to the Camera (eye) object in that prefab.

Next assign the component properties to these values:

• Pointer: Set this to the Parabolic Pointer object you created in Step 2
• Origin Transform: Set this to the origin of the tracking space. If you are using the SteamVR Unity Plugin, this is the [CameraRig] GameObject. This is the object that is actually moved when the player teleports.
• Head Transform: Set this to the transform of the player's head. This should be a child of the Origin Transform. If you are using the SteamVR Unity Plugin, this is the Camera (head) GameObject.
• Navmesh Animator: Set this to the Animator of the Vive Nav Mesh object created in Step 1.
• Fade Material: Set this to the material found in Vive-Teleporter/Art/Materials/FadeBlack.mat
• Controllers: Populate this with the SteamVR controller objects. If you are using the SteamVR [CameraRig] prefab, you should populate this with the Controller (left) and Controller (right) objects.