gistfile1.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using FluffyUnderware.Curvy;
using FluffyUnderware.Curvy.Controllers;

[System.Serializable]
public class ConveyorObject 
{
	public GameObject obj;
	public float tf;
	public Vector3 offset;
}

public class ConveyorBeltMachine : BaseFactoryMachine
{
	public CurvySpline spline;
	public float speed = 1.0f;
	public List<ConveyorObject> conveyorObjects = new List<ConveyorObject>();
	public bool snapToMiddle;

	void FixedUpdate()
	{
		if (spline) {
			if (isOn) {
				for (int i = 0; i < conveyorObjects.Count; i++) {
					// Find the position on the line using the time frame.
					Vector3 positionOnLine = spline.Interpolate (conveyorObjects[i].tf);

					// Find the perpendicular direction from the line tangent. This is a vector at a right angle
					// to the direction of line travel.
					Vector3 perpendicularDirection = -Vector3.Cross (spline.GetTangentFast(conveyorObjects[i].tf), Vector3.up);

//					float dot = -Vector3.Dot (conveyorObjects[i].offset, perpendicularDirection);
//					Debug.Log (dot);
//					if (dot < 0) {
//						perpendicularDirection = -perpendicularDirection;
//					}

					Vector3 newPosition;
					if (snapToMiddle) {
						newPosition = positionOnLine;
					} else {
						// The new position is the position on the line, and the right angle direction. We also add the original
						// offset magnitude so the item stays the same distance from the center as it travels.
						newPosition = positionOnLine + perpendicularDirection * conveyorObjects [i].offset.magnitude;
					}

					Debug.DrawLine (spline.transform.TransformPoint (positionOnLine), spline.transform.TransformPoint (newPosition));

					// We need to re-add the original Y position to the calculate position, so the item still remains
					// on top of the conveyor belt.
					Vector3 boxY = new Vector3 (0, conveyorObjects [i].offset.y, 0);

					// Move the rigid body to the newly calculated position.
					Rigidbody rigidbody = conveyorObjects[i].obj.GetComponent<Rigidbody> ();
					rigidbody.MovePosition (spline.transform.TransformPoint(newPosition) + boxY);

					// Increase the timeframe for the object.
					conveyorObjects[i].tf += conveyorObjects[i].tf * Time.fixedDeltaTime * speed;
				}
			}	
		}
	}

	void OnCollisionExit(Collision collision)
	{
		for (int i = 0; i < conveyorObjects.Count; i++) {
			if (collision.gameObject == conveyorObjects[i].obj) {
				conveyorObjects.Remove (conveyorObjects [i]);
				return;
			}
		}
	}

	void OnCollisionEnter(Collision collision)
	{
		Rigidbody rigidbody = collision.gameObject.GetComponent<Rigidbody> ();
		if (rigidbody) {
			// get nearest TF(Time Frame) and point on spline
			Vector3 objectLocalPosition = spline.transform.InverseTransformPoint(collision.transform.position);
			float startTimeFrame = spline.GetNearestPointTF(objectLocalPosition); 

			Vector3 positionAtTime = spline.Interpolate (startTimeFrame);
			Vector3 offsetPosition = objectLocalPosition - positionAtTime;

			ConveyorObject co = new ConveyorObject ();
			co.obj = collision.gameObject;
			co.tf = startTimeFrame;
			co.offset = offsetPosition;

			conveyorObjects.Add (co);
		}
	}
}