Oculus Rift DK2 + Leap Motion Unity Tutorial Chris Zaharia @chrisjz

Content Leap Motion VR Hand tracking using Leap SDK V2 (Skeletal Tracking) Object interaction Movement using Rift DK2 positional tracking

Introduces skeletal tracking Leap Motion SDK V2 Currently in beta Introduces skeletal tracking

Leap Motion VR Normally, need Leap mount to mount Leap to DK1/DK2. Can also use blue tac or other methods.

Augmented Reality Image API Infrared & Night Vision Enable in Leap Motion Control Panel > Settings > General > Allow Images Leap Oculus Passthrough Unity Package Next Leap Motion may have colour camera Leap Oculus Passhthrough Unity package allows integration of the infrared image passthrough in Unity. Can use to blend or show real world in VR.

Requirements IDE Leap Rift DK2 Unity Pro Leap Motion Driver Leap Motion V2 Tracking Beta (v.2.1.1.21671+) Leap Motion V2 Skeletal Assets (beta) Rift DK2 Unity 4 Pro Integration Need to use Unity Pro instead of free due to Leap integration using external plugins. Leap Motion V2 Skeletal Assets (beta) – found on Unity Assets store.

Scope Map physical hand and finger movements to 3D hand model and physics Grab physics objects (rigidbodies) by pinching Movement and jump using DK2’s positional tracker

Leap Motion - Unity File Structure Materials Blinn2.mat Gloves.mat Hands_Alt_blinn1.mat Models HandsRealistic.fbx Prefabs Hand Graphics RigidLeftHand.prefab RigidRightHand.prefab Hand Physics ThickRigidHand.prefab HandController.prefab Pick these files from the Leap Unity Assets package. Folders are bolded. Even some files included here you may not need.

LeapMotion … Scripts Hand Tools Utils HandController.cs FingerModel.cs HandModel.cs RiggedFinger.cs RiggedHand.cs RigidFinder.cs RigidHand.cs SkeletalFinger.cs SkeletalHand.cs Tools ToolModel.cs Utils LeapRecorder.cs LeapUnityExtensions.cs MagneticPinch.cs HandController.cs

Plugins [Include all files]

Attach hands to player Assumed that you’ve already integrated Rift with player Is compatible with Sixense’s Razer Hydra integration via script (see LeapHandExtendController.cs in tutorial)

Create empty GameObject called “LeapHandController” and place under OvrCameraController. Either attach the HandController prefab to game object or attach HandController.cs script. Fill out variables with the following:

Setup RigidLeftHand + RigidRightHand prefabs Check if both prefabs are set as follows or change accordingly. Red underline are suggested variables where the prefab’s may have different values than we want. Green underline is a suggestion. MagneticPinch.cs script allows user to grab rigidbodies by pinching fingers

Each finger must have the following variables, based on type of finger (i.e. index, pinky) and if it’s left (starts with L) or right (starts with R): For right hand, choose the [..]Arm3 mesh

Setup ThickRigidHand prefab Gives the hand collisions and physics Can therefore push objects

Magnetic Pinch Script Allows user to grab closest object which has a rigidbody Force Spring Constant sets the elasticity of the grip to object Magnetic Distance determines how close an object must be from a hand for it to be grabbed The magnetic pinch and hand physics conflict is due to the magnetic pinch script programmed to find the closest rigidbody which isn’t the hand’s graphics model which happens to be the physics hand model in this case. Warning: There is a conflict between Magnetic Pinch and enabling the Left/Right Physics Models. You’d need to fix this conflict by making the magnetic script ignore the hand’s physics

Grab Hand and Grabbable scripts As an alternative to Magnetic Pinch script Assign GrabHand.cs to hand graphic prefab Assign Grabbable.cs to rigidbody object to be grabbed Haven’t yet experimented much with this one so I can’t add much detail yet.

Hand Physics Interact with objects in a realistic way Grab small objects with one hand Grab larger objects with multiple hands Push/Pull other objects Other possibilities Grabbable objects must have colliders Currently, grasping objects with hands is still quite jittery. Future SDK or Leap hardware updates should improve on this hopefully.

Handle conflicts with other hand trackers This approach will hide/disable Sixense hands if leap motion detects leap hands in scene Start by extending Leap Motion’s HandController.cs

LeapHandExtendController.cs (1) using UnityEngine; using System.Collections; using Leap; public class LeapHandExtendController : HandController { protected Controller leap_controller_; protected void Awake () { leap_controller_ = new Controller(); }

LeapHandExtendController.cs (2) protected void LateUpdate () { if (leap_controller_ == null) return; CheckIfHandsEnabled (); } Currently we can’t override HandController’s Update() function, so we’ll use the LateUpdate() function instead.

LeapHandExtendController.cs (3) protected void CheckIfHandsEnabled () { Frame frame = leap_controller_.Frame(); HandList hands = frame.Hands; int num_hands = hands.Count; if (num_hands > 0) { TriggerSixenseHands (false); } else { TriggerSixenseHands (true); } Check the amount of leap hands visible, and if there are more than zero then disable Sixense (or any other) hand trackers.

Movement - DK2 Positional Tracking Move/Jump by using DK2’s positional tracking Move forward or backward by moving head in those directions Either rotate or strafe sideways by moving head left/right Jump by popping head upwards Could crouch too by popping head downwards User should normally be positioned directly in front of DK2’s tracker

Logic - Positional Tracking Movement Create/modify your player input controller script, attached to player Head position is calculated by subtracting the initial local position of the main camera, of when scene is loaded, from its current position Create configurable Vector3 variables for: Sensitivity – strength multiplier of movement or jump actions Minimum – The minimum position that the Rift must be away from the centre position, for the action to actually be triggered Movement will use the X (-left/+right) and Z axis (+forward/-backward) in the direction of the camera as a variable sent to the Character Motor’s inputMoveDirection variable Jump will use the Y axis and will be mapped to the Character Motor’s inputJump variable Vector3 mapping to movements: Left = negative X Right = positive X Forward = positive Z Backward = negative Z Jump = positive Y (Additionally) Crouch = negative Y

Code – Positional Track Movement [RequireComponent(typeof(CharacterMotor))] public class FPSInputController : MonoBehaviour { … public bool ovrMovement = false; // Enable move player by moving head on X and Z axis public bool ovrJump = false; // Enable player jumps by moving head on Y axis upwards public Vector3 ovrControlSensitivity = new Vector3(1, 1, 1); // Multiplier of positiona tracking move/jump actions public Vector3 ovrControlMinimum = new Vector3(0, 0, 0); // Min distance of head from centre to move/jump public enum OvrXAxisAction { Strafe = 0, Rotate = 1 } public OvrXAxisAction ovrXAxisAction = OvrXAxisAction.Rotate; // Whether x axis positional tracking performs strafing or rotation private GameObject mainCamera; // Camera where movement orientation is done and audio listener enabled private CharacterMotor motor; // OVR positional tracking, currently works via tilting head private Vector3 initPosTrackDir; private Vector3 curPosTrackDir; private Vector3 diffPosTrackDir; Note – entire code for class is not here, only relevant code. If you’d like some help on this, feel free to contact me @chrisjz. mainCamera needs to be declared as either the only camera following the player, or one of the 2 Oculus Rift cameras.

Start + Update void Start() { … initPosTrackDir = mainCamera.transform.localPosition; } void Update() { // Get the input vector from OVR positional tracking if (ovrMovement || ovrJump) { curPosTrackDir = mainCamera.transform.localPosition; diffPosTrackDir = curPosTrackDir - initPosTrackDir; Set current tracking position as the camera’s local positon, then calculate the difference position by subtracting the initial camera position from the current.

Update (continued) … if (ovrMovement) { if (diffPosTrackDir.x <= -ovrControlMinimum.x || diffPosTrackDir.x >= ovrControlMinimum.x) { if (ovrXAxisAction == OvrXAxisAction.Strafe) { diffPosTrackDir.x *= ovrControlSensitivity.x; } else { transform.Rotate(0, diffPosTrackDir.x * ovrControlSensitivity.x, 0); diffPosTrackDir.x = 0; } If head position is further than the minimum from the centre, then set the direction to move multiplied by sensitivity, otherwise do not move in that direction.

Update (continued) … if (diffPosTrackDir.z <= -ovrControlMinimum.z || diffPosTrackDir.z >= ovrControlMinimum.z) { diffPosTrackDir.z *= ovrControlSensitivity.z; } else { diffPosTrackDir.z = 0; } directionVector = new Vector3(diffPosTrackDir.x, 0, diffPosTrackDir.z); directionVector is used afterwards to set the movement directions and strength.

Update (continued) if (ovrJump) { if (diffPosTrackDir.y > ovrControlMinimum.y) { motor.inputJump = true; } else { motor.inputJump = false; } motor.inputJump = Input.GetButton ("Jump"); … motor.inputMoveDirection = mainCamera.transform.rotation * directionVector; // performs actual movement If jump via positional tracking : Enabled, then trigger jump action if camera’s difference position is above the set minimum Y axis position Disabled, then map jump keyboard key to jump action

}