SetTransform Causing hand to spin constantly?

[user-214315690]

Hi,

I have another post on here about trying to set a hand into a fixed pose but it's not had any views or responses so i thought i would try another approach.

I have loaded the pose i want from an xml (serialized leap.hand object) and have then used the "SetTransform" method on the hand object to set it to the hand position and rotation from the live data. However, this causes the hand to constantly spin. The hands position is correct and it moves with the live data whilst maintaining the fixed pose that i need, but for some reason it is spinning like crazy.

I'm guessing that there is a known bug with the API.

[AlexColgan]

Have you considered reading the palm position, palm normal, and hand direction instead of attempting to use SetTransform? SetTransform transforms a bone into a position and rotation -- it sounds like the rotation is not a change in orientation over time, but a value based on the bone's orientation (which would result in continuous rotation).

[user-214315690]

EDIT: Ok so i tried it with the code from the original post and it moves the hand with the live data, but it doesn't rotate the hand when i rotate my hand.

[AlexColgan]

If you're mapping the palm normal to the virtual hand's palm normal, then it should rotate, as the palm normal is just a vector orthogonal to the palm. Changes in palm rotation should result in changes to that vector's direction.

[user-214315690]

This is my code:

public static Hand SetHandInPose(Hand hand, Hand pose)
    {
        if(hand == null)
        {
            Debug.Log("Hand is null, so returning that");
            return hand;
        }
        if(pose == null)
        {
            Debug.Log("The loaded pose is null, so let's just return the original hand");
            return hand;
        }

        Hand h = pose;

        Quaternion handRotOffset = pose.Rotation.ToQuaternion() * Quaternion.Inverse(hand.Rotation.ToQuaternion());
        //Debug.Log("The rotational offset is: " + handRotOffset.eulerAngles);
        Vector offset = hand.PalmPosition - pose.PalmPosition;

        h.Rotation = hand.Rotation;//(h.Rotation.ToQuaternion() * handRotOffset).ToLeapQuaternion();
        h.PalmPosition += (offset.ToVector3()).ToVector();
        h.WristPosition += (offset.ToVector3()).ToVector();

        for(int f = 0; f< h.Fingers.Count; f++)
        {
            for(int i = 0; i < h.Fingers[f].bones.Length; i++)
            {
                //offset = hand.Fingers[f].bones[i].Center - pose.Fingers[f].bones[i].Center;     

                //if (h.Fingers[f].bones[i].Type == Bone.BoneType.TYPE_METACARPAL) continue;
                h.Fingers[f].bones[i].Center += (offset.ToVector3()).ToVector();
                h.Fingers[f].bones[i].NextJoint += (offset.ToVector3()).ToVector();
                h.Fingers[f].bones[i].PrevJoint += (offset.ToVector3()).ToVector();
                h.Fingers[f].bones[i].Rotation = hand.Fingers[f].bones[i].Rotation;
                //h.Fingers[f].bones[i].Rotation = (h.Fingers[f].bones[i].Rotation.ToQuaternion() * handRotOffset).ToLeapQuaternion();
                h.Fingers[f].bones[i].Direction = (h.Fingers[f].bones[i].NextJoint - h.Fingers[f].bones[i].PrevJoint);
                h.Fingers[f].bones[i].Center = (h.Fingers[f].bones[i].PrevJoint + h.Fingers[f].bones[i].NextJoint) / 2f;
            }
            h.Fingers[f].Direction = h.Fingers[f].GetBone(Bone.BoneType.TYPE_INTERMEDIATE).Direction;
        }
        return h;
    }