*

Unity/Assets/Scripts/Animation/EngineRod.cs

@@ -0,0 +1,51 @@
+using UnityEngine;
+using System.Collections;
+
+public class EngineRod : MonoBehaviour
+{
+    public Transform anchor;
+    public Transform piston;
+
+    public float rodLength;
+    public Vector3 upVector;
+
+    private Vector3 startPosition;
+    private Quaternion rotation;
+    private Quaternion pistonRotation;
+    // Use this for initialization
+    void Start ()
+    {
+        upVector = piston.position - anchor.position;
+
+        rodLength = (transform.localPosition - transform.parent.InverseTransformPoint(piston.position)).magnitude;
+
+        upVector.Normalize();
+        startPosition = transform.localPosition;
+        upVector = transform.parent.InverseTransformVector(upVector);
+
+        rotation = transform.localRotation;
+        pistonRotation = piston.localRotation;
+    }
+
+    public float projectionDistance;
+	// Update is called once per frame
+	void Update () {
+	    if (anchor != null)
+	    {
+	        transform.position = anchor.position;
+
+	        Ray r = new Ray(startPosition, upVector);
+	        var localPosProjected = r.Project(transform.localPosition);
+	        projectionDistance = (localPosProjected - transform.localPosition).magnitude;
+
+	        float pistonOffset = Mathf.Sqrt(rodLength*rodLength - projectionDistance*projectionDistance);
+
+	        float angle = (90.0f -  Mathf.Asin(pistonOffset/rodLength) * Mathf.Rad2Deg) *- Mathf.Sign(Vector3.Dot(transform.localPosition - localPosProjected, Vector3.forward));
+
+
+	        transform.localRotation = Quaternion.AngleAxis(angle, Vector3.right) * rotation;
+       
+            piston.localRotation = pistonRotation * Quaternion.AngleAxis(-angle, Vector3.right);
+        }
+	}
+}