Why is it so unnecessarily complex to get position and rotation?

[Caliber-Mengsk]

EDIT: Just a note, this is using the unitypackage Orion Beta 4.0.1 (newest version when I made this post)

I've just started messing with the leap motion, so maybe I'm just blind to something, but why is it so complex to get things positions and rotations? I can understand that it's converting things from the leaps coordinate system to unity's, but still. I've been messing with it for hours, looking through the documentation, simply trying to get an object to be in the same position and rotation as the palm of the hand. That's it, pretty simple. Off of that would be a push button like menu, just like is shown in the orion demo. But I have been messing with it for hours and hours (porbably at least 8 hours at this point) and have only gotten the position working after just messing around, since none of the examples in the documentation seemed to actually work. It's rather annoying.

Getting the hands to show up was easy enough, but everything past that has been horrible. I had to switch the y and z axis, as well as make x and z negative just to get the position right. Here's my code:

                Vector3 newPos = hand.PalmPosition.ToUnity()/1000;
                newPos = new Vector3(-newPos.x, -newPos.z, newPos.y);
                guiController.transform.localPosition = newPos;

And ToUnityScaled seems to be giving me the same value as ToUnity, so that doesn't help. I still have yet to figure out what I have to do to get rotations that actually work. The documentation says that a Leap.Vector should have a forward, in which case I could set the rotation equal to the forward, but it's not actually there when you try to code it.

Why isn't there a simple thing like "ToUnity" that just gives the world position in a vector3 or a world rotation in a quaternion? I'm not trying to be a jerk, but it's just horrible as far as ease of use. Please tell me if I'm doing something wrong and there is something that's simple and easy and doesn't require complex manipulations of data that should just be output like the engine expects.

I can understand it's a complex system, and that the orion stuff is new, but still, it's upsetting how hard it is to get information. You can't just do something like hand.palm.rotation as it is, and you should be able to. Like I said, I still have yet to figure out how to convert the values of rotation to a useable form. The closest I've gotten was something like (hand.PalmNormal.ToUnity()/Mathf.PI)*180. Doing that actually scales everything right at least, but all the angles are messed up, and seem to have gimbal locking on them when you turn too far.

Am I really just missing something?

[Joe_Ward]

First off, I apologize that the documentation is lagging behind. The API is still in active development and will continue to be for at least a few more iterations of the beta.

For what you are trying to do, it would appear easiest to attach your menu directly to the Unity Hand objects (and turn it on or off as needed). As children of the hand, they would then move with it automatically.

Beyond that, if you are trying to do some calculations that should correlate with the Unity hand models, you should get the data from either the HandModel object itself, or from LeapProvider.CurrentFrame this data is already transformed from the Leap Motion coordinate system to the Unity coordinate system relative to the Unity LeapHandController object. You don't need to use ToUnity() or ToUnityScaled() on the Vectors in this case, since the transformation has already been done -- just use ToVector3() to create a Unity Vector3 object when necessary. For matrices that contain rotations, you can use the Matrix.Rotation() extension to get a Unity Quaternion object. So for the hand rotation, something like hand.Basis.Rotation() should work.

Also, our Unity HandModel class, which all the asset hands use provide functions like GetPalmPosition() and GetPalmRotation() which give you that hands attributes as Unity Vector3 and Quaternion objects.

If you get a frame of data directly from the Controller. That data will still be in the Leap Motion coordinate system, with its origin at (0,0,0). To make the data correlate to a displayed hand, you would have to repeat the same transformation that the LeapProvider object already did. There typically isn't a reason to do this -- the only reason I can think of is if you aren't displaying hands at all and are just using the data in some abstract, mathematical way.

Note that ToUnityScaled() and ToUnity() were broken in the first Orion release. I thought we fixed this before 4.0.1 was released, but maybe it didn't make the cut.

[Caliber-Mengsk]

So that's probably my problem then as I was using the frame data directly from the controller since that's what everywhere I searched for (and I think the documentation too) had said to get. I'll have to try it out when I get off work tonight. I read that you didn't have to use the ToUnity or ToUnityScaled, but I wasn't getting hardly any other results with anything else. It seems that the documentation for the orion stuff for unity is pretty much an exact copy, thus it's not helping when problems arise. I understand that it's still in beta, but a direct copy paste probably does more damage than saying it's just not documented yet.

That all said, I did try to just parent to the left hand (like I said, was trying to effectively duplicate the orion demo's menu) and it wasn't moving with it or anything. That's why I started coding it. I did try that in 4.0.0 instead of 4.0.1 though, but now that I think about it, I didn't use the collider hand either. Was it suppose to be a child of the collider? Or should being a child of the mesh work? Another thing I'll try out.

It does seem that I just wasn't seeing something (that being the LeapProvider object over the controller). As stated, I'll try it out when I get out of work, I'll let you know if I'm still having trouble.

[Caliber-Mengsk]

Ok, so setting it as a child object of the hand, still does nothing, so that's broken or I'm still somehow doing something wrong on that end. Beside that, using the leap provider does work.

                guiController.transform.position = hand.PalmPosition.ToVector3();
                guiController.transform.rotation = hand.Basis.Rotation();

That code works perfectly. (gui controller being an empty object with children offset to the right position/rotation.) I know it's still in beta, but you may want to update that in the documentation as hand has the example

                Frame frame = controller.Frame (); // controller is a Controller object
                HandList hands = frame.Hands;
                Hand firstHand = hands [0];

and obviously that's not right, and makes it hard to get started since the example given is for the old system.

[Joe_Ward]

To attach a Unity object to a hand, you need to make the object a child of the palm, forearm, or a finger bone, not the root hand object -- essentially, you can find a suitable attachment point by observing the transform of the object in the editor while playing; if the object moves, then any children attached to it will also move.

This doesn't really work with the CapsuleHand since it generates all its components at runtime. You can attach objects to the physics hands. It should also be possible to create a sub-class of CapsuleHands that supported a child object.

In Blocks, we used the same approach that you used above, with the small difference that the rotation was set so that the controls always faced the camera.

[mgummelt]

GetPalmRotation

There is no HandModel.GetPalmPosition() or HandModel.GetPalmRotation(). Were these removed?

[Joe_Ward]

Those methods of HandModel still exist. Are you looking at IHandModel?

[mgummelt]

Yes, actually, I was. I realized that a little bit ago. I've since switched to HandModel instead of IHandModel and it's much more convenient, thanks!

I think it was using IHandModel in the example I used as my base (the extended finger detector), and I didn't change it. Heh.

[BrianSch]

I also struggled with this for a long time. I'm guessing you want to do something like this?

Here's how I did it. I created a world space UI and attached it to the palm of the left hand and disabled it.

I attached the leap prefab Palm Direction Detector script to the hand so the UI only shows when you have your palm facing up. Setting the On Activate an On Deactivate triggers to my own script.

Then wrote a script to enable and disable the UI when the palm direction detector script triggers Activate/Deactivate.

using UnityEngine;
using System.Collections;
using Leap.Unity;
public class EnableHandUI : MonoBehaviour 
{
    public GameObject handUI;
    void OnDisable()
    {
        // Disable the UI if the hand goes out of range and gets disabled
        if(handUI.activeSelf)
        {
            handUI.SetActive(false);
        }
    }
    // enable the UI when the palm is facing up
    public void OnPalmUp()
    {
            handUI.SetActive(true);
    }
    // disable the UI when the palm is not up
   public void OnPalmNotUp()
    {
        handUI.SetActive(false);
    }
}

Hope that helps.

The way I've been getting the hand position/rotation (for spawning things at the palm) is like this:

public Leap.Unity.RiggedHand hand; // then taking the hand I want from the hierarchy and setting it in the inspector
hand.GetPalmPosition(); // gives me the unity coordinates of the palm
hand.GetPalmRotation();

There may be a better way to do this but like everyone has said the documentation is lacking.

[macandili09]

Hey sir i know its an old entry but can you teach me how did you get the position of the palm up.

[haeisens]

Hello! I was reading through this thread, and was having the same issues as the OP. I was wondering if there's a way to move an object to a hand's palm position without parenting it to the hand model. I have an object I want to sometimes snap to the hand, but which should otherwise not be a child of it. I could always parent and deparent it, but I was wondering if there's a better way.

I'd ideally like to get the palm position from frame.Hands and just set the object's position to the retrieved hand position, but when I try to get this position, it's far off from the hands. I've tried transforming the position from the hand model's local to world position, but this still doesn't yield the results I want. Any suggestions?

[Bren]

Have you had a look at the Attachments components in the core assets? Documentation is not great but they may be what you're looking for.