Setting 'Last Object Touched Adjusted Mass' on Hand Creation?

Tags: #<Tag:0x007f86980bbed8> #<Tag:0x007f86980bbd48>

zmDev 2018-11-07 14:52:58 UTC #1

Hello!

I am working on a project with the Leap Motion toolkit in Unity and am having trouble figuring out a way to set the 'Last Object Touched Adjusted Mass' value of the Contact Bone (Script) when the Right/Left Interaction Hand Contact Bones are created in the scene (when a hand comes into view of the Leap Motion sensor). Currently this value is set to '0' when the Right/Left Interaction hand Contact Bones are created, and I am looking to set this value to something other than 0 (say, '5') when the creation of the contact bones happens.

I've been looking through the code to determine where these values are actually instantiated but am struggling to find how it can be set on creation. I've found the following, which seems to be where the magic happens.

    IInteractionBehaviour interactionObj;
    if (interactionController.manager.interactionObjectBodies.TryGetValue(collision.rigidbody, out interactionObj)) {
      _lastObjectTouchedAdjustedMass = collision.rigidbody.mass;
      if (interactionObj is InteractionBehaviour) {
        switch ((interactionObj as InteractionBehaviour).contactForceMode) {
          case ContactForceMode.UI:
            _lastObjectTouchedAdjustedMass *= 2F;
            break;
          case ContactForceMode.Object:
          default:
            if (interactionHand != null) {
              _lastObjectTouchedAdjustedMass *= 0.2F;
            }
            else {
              _lastObjectTouchedAdjustedMass *= 3F;
            }
            break;
        }
      }

I've tried playing with the values in this portion of the code (changing numbers, using += instead of *=, even trying '=' to set the value to a specific number) and have had no luck - the contact fingerbones still spawn into the scene with a 'Last Object Touched Adjusted Mass' of 0.

Am I doing something wrong or looking in the wrong place? This is my first time using the Leap Motion kit and would very much appreciate any help at all.

All the best!

jselstad 2018-11-13 17:29:30 UTC #2

That code gets triggered upon contact with a rigidbody; it adjusts its own mass compared to whatever it is currently touching (the mass of the interaction hands should not matter until a collision occurs).

If you need that value to be set to something before any collisions have occurred for some reason, you can initialize that value at line 108 in this script by setting it equal to some number:

github.com

leapmotion/UnityModules/blob/master/Assets/LeapMotion/Modules/InteractionEngine/Scripts/Internal/ContactBone.cs

/******************************************************************************
 * Copyright (C) Leap Motion, Inc. 2011-2018.                                 *
 * Leap Motion proprietary and confidential.                                  *
 *                                                                            *
 * Use subject to the terms of the Leap Motion SDK Agreement available at     *
 * https://developer.leapmotion.com/sdk_agreement, or another agreement       *
 * between Leap Motion and you, your company or other organization.           *
 ******************************************************************************/

using UnityEngine;
using System.Collections.Generic;

namespace Leap.Unity.Interaction {

  /// <summary>
  /// Contact Bones store data for the colliders and rigidbodies in each
  /// bone of the contact-related representation of an InteractionController.
  /// They also notify the InteractionController of collisions for further
  /// processing.
  ///

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However, I suspect it will not accomplish what you are trying to do... what are you trying to do?