Spring Follow Camera (C#)

So, I've written spring cameras before in other APIs, but I can't seem to wrap my head around Unity's (I'm still fairly new to it). Here is my SpringFollow camera script in C#

Code (csharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class SpringFollow : MonoBehaviour
5. {
6.     public Transform Target;
7.     public Camera SpringCamera = Camera.mainCamera;
8.  
9.     public float Stiffness = 1800.0f;
10.     public float Damping = 600.0f;
11.     public float Mass = 50.0f;
12.     public Vector3 DesiredOffset = new Vector3(0.0f, 3.5f, -4.0f);
13.     public Vector3 LookAtOffset = new Vector3(0.0f, 3.1f, 0.0f);
14.  
15.     private Vector3 desiredPosition = Vector3.zero;
16.     private Vector3 cameraVelocity = Vector3.zero;
17.  
18.     // Use this for initialization
19.     void Start ()
20.     {
21.    
22.     }
23.  
24.     void FollowUpdate()
25.     {
26.         Vector3 stretch = SpringCamera.transform.position - desiredPosition;
27.         Vector3 force = -Stiffness * stretch - Damping * cameraVelocity;
28.  
29.         Vector3 acceleration = force / Mass;
30.  
31.         cameraVelocity += acceleration * Time.deltaTime;
32.  
33.         SpringCamera.transform.position += cameraVelocity * Time.deltaTime;
34.  
35.         Matrix4x4 CamMat = new Matrix4x4();
36.         CamMat.SetRow(0, new Vector4(-Target.forward.x, -Target.forward.y, -Target.forward.z));
37.         CamMat.SetRow(1, new Vector4(Target.up.x, Target.up.y, Target.up.z));
38.         Vector3 modRight = Vector3.Cross(CamMat.GetRow(1), CamMat.GetRow(0));
39.         CamMat.SetRow(2, new Vector4(modRight.x, modRight.y, modRight.z));
40.  
41.         desiredPosition = Target.position + TransformNormal(DesiredOffset, CamMat);
42.         Vector3 lookat = Target.position + TransformNormal(LookAtOffset, CamMat);
43.  
44.         SpringCamera.transform.LookAt(lookat, Target.up);
45.         //SpringCamera.projectionMatrix = Matrix4x4.Perspective(SpringCamera.fieldOfView, SpringCamera.aspect, SpringCamera.near, SpringCamera.far);
46.  
47.         print("cam = " + SpringCamera.transform.position.ToString());
48.     }
49.    
50.     // Update is called once per frame
51.     void Update ()
52.     {
53.         FollowUpdate();
54.     }
55.  
56.     Vector3 TransformNormal(Vector3 normal, Matrix4x4 matrix)
57.     {
58.         Vector3 transformNormal = new Vector3();
59.         Vector3 axisX = new Vector3(matrix.m00, matrix.m01, matrix.m02);
60.         Vector3 axisY = new Vector3(matrix.m10, matrix.m11, matrix.m12);
61.         Vector3 axisZ = new Vector3(matrix.m20, matrix.m21, matrix.m22);
62.         transformNormal.x = Vector3.Dot(normal, axisX);
63.         transformNormal.y = Vector3.Dot(normal, axisY);
64.         transformNormal.z = Vector3.Dot(normal, axisZ);
65.  
66.         return transformNormal;
67.  
68.     }
69. }
70.  

I originally did this code in XNA a while back, which may be painfully evident with me manually adding in the TransformNormal(Vector3 normal, Matrix4x4 matrix) function. The result I'm getting from this is a camera that's attached to the side of my target and has twitchy behavior. So what am I doing horribly wrong?

 

try calling it from within LateUpdate instead of Update.. (twitching)

 

Well, the twitching still happens, but it smoothed out Improvement?