Transforms on human model do not move independently

Unity Engine
1

Hi guys,

I’m quite new to Unity so I could need some advice. I have imported the human model called “carl” from the Asset Store. It has got the following joint hierarchy:

  • carl

  • Hips

  • LeftUpLeg

  • RightUpLeg

  • Spine

  • Spine1

  • Spine2

  • LeftShoulder

  • LeftArm

  • Neck

  • RightShoulder

  • RightArm

I wrote some piece of code that moves the joints of the model - represented as Transforms - sequentially.

/*
 * Perform some example movements
 */
SequencedMotion s1,s2,s3;

Motion neckRotation = new Motion(Joints.Neck, Sides.Left, MotionTypes.Rotation);
// (motion, starting time, duration, start angle, end angle)
s1 = new SequencedMotion(neckRotation, 0, 3, 0, 80);
sequencer.Add(s1);

Motion armAbduction = new Motion(Joints.Shoulder, Sides.Left, MotionTypes.Abduction);
s2 = new SequencedMotion(armAbduction, 1, 2, 90, 180);
sequencer.Add(s2);

What the sequencer basically does is updating the joints depending on the time that has passed.

/**
 * Updates the state of the motions that were added to the sequencer
 */
public void Update() {
	float time = Time.time;
	
	foreach(SequencedMotion m in motions) {
		if(time >= m.GetTimeStart()) {
			adjustPosition (m.GetMotion(), m.GetCurrentPosition(time));
		}
	}
}


private void adjustPosition(Motion m, float position) {
	// Neck
	if(m.GetJoint().Equals(Joints.Neck)) {
		
		if(m.GetMotionType().Equals(MotionTypes.Rotation)) {
			lm.AbsNeckRotation(position, m.GetSide());
		}
	
	// Shoulder
	} else if(m.GetJoint().Equals(Joints.Shoulder)) {	

		if(m.GetMotionType().Equals(MotionTypes.Abduction)) {
			lm.AbsShoulderAbduction(position, m.GetSide());
		}
		
	}

}

What now happens is that the neck joint moves properly but when the arm starts moving after a second the arm does not only move in the direction it is supposed to but also performs the rotation that was originally assigned to the neck. I found on Google that you should be aware that Transforms are also performed on children of Transforms but in this case there should not be any parent-child-relationships:

neck = root.FindChild("Hips/Spine/Spine1/Spine2/Neck");
lShoulder = root.FindChild("Hips/Spine/Spine1/Spine2/LeftShoulder/LeftArm");
rShoulder = root.FindChild("Hips/Spine/Spine1/Spine2/RightShoulder/RightArm");

The manipulation of the joints is implemented by altering the euler angles:

	public void AbsNeckRotation(float degrees, Sides direction) {
		int rotationFactor = -1;
		
		if(direction.Equals(Sides.Right)) {
			rotationFactor = 1;
		}
		
		Vector3 newEulerAngles = new Vector3(
									neck.eulerAngles.x,
									rotationFactor*degrees,
									neck.eulerAngles.z
								 );
		neck.eulerAngles = newEulerAngles;
	}

	public void AbsShoulderAbduction(float degrees, Sides side) {
		// Move left side by default
		Transform shoulder = lShoulder;
		int rotationFactor = -1;
		
		if(side.Equals(Sides.Right)) {
			shoulder       = rShoulder;
			rotationFactor = 1;
		}
		
		// Why does this even work? There should be a much easier solution.
		Vector3 newEulerAngles = new Vector3(
									neck.eulerAngles.x,
									neck.eulerAngles.y,
									Add360(neck.eulerAngles.z-rotationFactor*90, rotationFactor*degrees)
								 );
		shoulder.eulerAngles = newEulerAngles;
	}

Does anyone have a clue how this behaviour is possible? I am quite lost :frowning: Thank you!

2

Nevermind people. It was a copy paste-mistake. In the AbsShoulderAbduction-method I set the new angle by referring to the NECK’s x- and y-component -.-

Thanks anyway for reading!