ForceMode.Acceleration

Hello,

I’m trying to get an object to accelerate and increase speed, and it doesn’t look like the object is doing that. Here’s my code:

using UnityEngine;
using System.Collections;

public class Acceleration : MonoBehaviour {
	public float ForceSpeed;
	
	// Update is called once per frame
	void FixedUpdate () {
		rigidbody.AddForce(Vector3.right * Time.deltaTime * ForceSpeed, ForceMode.Acceleration);	
		print(ForceSpeed);
	
	}

}

The object looks like it’s moving at the same speed. What do I need to do? Also, how do I print ‘ForceSpeed’ every three seconds? I’ve checked online and I still can’t seem to get it. Any help is appreciated. Thank you for your time.

This script should work, but the values of ForceSpeed and rigidbody.drag may sabotage it! You’re multiplying ForceSpeed by Time.deltaTime, which in FixedUpdate means a resulting acceleration 50 times lower than expected. Besides this, rigidbody.drag creates a friction proportional to the speed, what limits the rigidbody velocity.

Remove the multiplication by Time.deltaTime, and set Drag to zero. If you still can’t get the desired result, use ForceMode.Force: a force applied in this mode in FixedUpdate results in a constant acceleration equal to force/mass. If you want an acceleration independent of the rigidbody mass, multiply ForceSpeed by rigidbody.mass:

void FixedUpdate () {
   // ForceMode.Force is default, thus you don't need to specify it:
   rigidbody.AddForce(Vector3.right * rigidbody.mass * ForceSpeed);
}

Why are you printing ForceSpeed? Isn’t it constant? If you want to monitor the rigidbody speed, print rigidbody.velocity.ToString() instead.