Jerky object movement when lerping/transforming position

Questions & Answers
1

Hi

As the title says, moving/lerping my object leads to super jerky/bumpy movement. I’m not sure exactly why, though I’m new to C# so I know I’ve probably made an egregiously noobish error.

If you’d like to see it, here is a quick ~10 second video: https://drive.google.com/file/d/0Bxh7lmUEfLYYcHNTOFJ2bGZtRlU/view?usp=sharing

Here are the parts of the script that seem to be causing all the trouble:

void FixedUpdate () {
		leftScriptPosition = new Vector3 (-1, transform.position.y, transform.position.z);
	}

IEnumerator moveLeft(Vector3 leftScriptPosition) {
    		float t = 0;
    		while (t < 1) {
    			t += Time.deltaTime;
    			transform.position = Vector3.Lerp (transform.position, leftScriptPosition, laneChangeSpeed * Time.deltaTime);
    			yield return null;
    		}
    	}

Thanks heaps :slight_smile:

2

Use default rigidbody on sphere. Place a plane under a sphere in Z direction.

using UnityEngine;
using System.Collections;

/// <summary>
/// Ball controller. 
/// Ball roll in Z+ direction. Tracks change on X axis.
/// </summary>
[RequireComponent(typeof(Rigidbody))]
public class BallController : MonoBehaviour 
{
	public float acceleration = 1f;				// acceleration
	public float maxSpeed = 4f;					// nax speed
	public float jumpPower = 500f;				// jump power
	public int trackMin = -2;					// if -2 it means you can move twice to left [there is 5 tracks if -2 & 2]
	public int trackMax = 2;					// if 2 it means you can move twice to right [there is 5 tracks if -2 & 2]
	public float trackWidth = 2f;				// width of the single track
	public float trackChangeSpeed = 3f;			// how fast transition between tracks

	private float _currentSpeed = 0f;			// current speed
	private int _track = 0;						// target track
	private bool _onTrack = true;				// true if ball is on correct track
	private Rigidbody _rb;						// rigidbody handler
	private Vector3 _spawn;						// spawn position, used to keep the x coord

	void Start()
	{

		_rb = GetComponent<Rigidbody>();
		_spawn = transform.localPosition;
	}

	void FixedUpdate()
	{
		// jump if grounded only [you should use ray casting for detect a ground]
		if(_rb.velocity.y <= 0.005f && _rb.velocity.y >= -0.005f)
		{
			if(Input.GetKey(KeyCode.W))
			{
				_rb.AddForce(new Vector3(0f, jumpPower, 0f));
			}
		}

		// can change to next track if is on current track only [can not change on track change]
		if(_onTrack)
		{
			// move left
			if(Input.GetKey(KeyCode.A))
			{
				ToLeftTrack();
			}
			// move right
			else if(Input.GetKey(KeyCode.D))
			{
				ToRightTrack();
			}
		}
	}

	void Update()
	{
		// track change
		if(!_onTrack)
		{
			transform.localPosition = new Vector3(Mathf.MoveTowards(transform.localPosition.x, _spawn.x + _track * trackWidth, Time.deltaTime * trackChangeSpeed), transform.localPosition.y, transform.localPosition.z);
	
			if(transform.localPosition.x == (_spawn.x + _track * trackWidth))
			{
				_onTrack = true;
			}
		}

		// increase a speed & move
		_currentSpeed = Mathf.MoveTowards(_currentSpeed, maxSpeed, Time.deltaTime * acceleration);
		transform.position = new Vector3(transform.position.x, transform.position.y, transform.position.z + _currentSpeed * Time.deltaTime);
	}

	void ToLeftTrack()
	{
		if(_track > trackMin)
		{
			_track--;
			_onTrack = false;
		}
	}

	void ToRightTrack()
	{
		if(_track < trackMax)
		{
			_track++;
			_onTrack = false;
		}
	}
}