Swimming Hands with Hololens Movement

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Cyberelle 2020-04-07 15:00:52 UTC #1

I'm working on an AR project in Unity using the Hololens with a leap motion mounted on top of it. The goal is to get the virtual hands perfectly aligned with the user's physical hands so the virtual hands can be made invisible. With the device offset mode on 'manual head offset' the alignment is pretty good. However, when moving around, the hands slightly move along with the head, creating a swimming effect. In other words, if the hands are kept perfectly still and the head is moved closer, the hands drift a couple of centimeters away from head, following its movement.

Temporal warping mode seems to be the setting that should fix this problem but I have tried every option, the manual one with a wide range of values, and this does not show any improvement. I have tried many other things and settings (in different versions of Unity) but nothing seems to work.

Does anyone have any idea how to solve this? Thanks in advance!

dankirby 2020-04-09 13:59:07 UTC #2

As well as temporal warping and ensuring that the offset is correctly set, look at the timewarp function, how this is set and adjust to test. This swimming effect might be caused by timewarp not working.

The Building an AR Camera Rig section of this documentation might help guide you in the right direction:

https://developer-archive.leapmotion.com/documentation/v2/unity/unity/Unity_Custom_Rig.html

Cyberelle 2020-04-15 13:48:02 UTC #3

Thanks for the suggestion! I can't find a timewarp function anywhere in the code. Could you explain this in a little more detail?

The documentation seems to be referencing an old version of the Unity assets so some of the scripts mentioned were missing in my project. I tried to build a custom AR rig following the steps as closely as possible but this didn't change anything and there was no mention of timewarp.

dankirby 2020-04-21 15:53:37 UTC #4

Can you let me know which versions of Unity and Leap Motion software that you are using and a post a copy of your offset settings?

dankirby 2020-04-22 16:25:32 UTC #5

The relevant code that you need can be found via the link below and the relevant function is TemporalWarpingMode:

github.com

leapmotion/UnityModules/blob/cb789334c083fcfc0c347432c323eb47a7549edd/Assets/LeapMotion/Core/Scripts/LeapXRServiceProvider.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;
using Leap.Unity.Attributes;

#if UNITY_2018_2_OR_NEWER
using UnityEngine.Rendering;
#endif

namespace Leap.Unity {

  /// <summary>

This file has been truncated. show original

This documentation is old, but provides a decent overview of what Temporal Warping does:

https://developer-archive.leapmotion.com/documentation/v2/unity/unity/Unity.Prefab.LMHeadMountedRig.html