Unity, Moving object by friction + rotation

Question

I am desperately looking everywhere for a solution to this problem but did not find any possibility yet, maybe you can help me out: I am making a simple test in which a kind of cylinder can rotate itself and moving on a flat platform by friction. I have rigid body, mesh collider attached already and a script to control the rotation. It can be moving fast or slow depends on its rotation speed. The script is as follow:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerController : MonoBehaviour {

public float rollingSpeed;
public float gravity;

// Update is called once per frame
void FixedUpdate()
{
    transform.Rotate(rollingSpeed, 0.0f, 0.0f);
    GetComponent<Rigidbody>().AddForce(0.0f, -gravity, 0.0f);
}
}

The problem is when I run the Play mode, this cylinder is rotating itself but staying in the same position! (in fact it is moving back and forth very slightly), I really dont know what is the cause, I tried to increase the friction parameters, add physical materials, and even adding a second force downward (like gravity) but it doesnt work. Can anyone please have a solution for this? Thank you guys so much!

MT-FreeHK MT-FreeHK · Accepted Answer · 2018-08-03T14:32:04

Rotate is just transform eular coordinate without any force, use AddTorque instead for physical movement.

For example,

GetComponent<Rigidbody>().AddTorque(new Vector3(1, 0, 0) * rollingSpeed * Time.deltatime);

Unity, Moving object by friction + rotation

1 Answers