How can I make an object stick to a surface, but still let me add forces to the object.

Questions & Answers
1

I am trying to make a game with a pipe and ball , however whenever you go on one of the sides of tube and try to move the opposite direction the balls just flys through the air. I want to make it so the ball is stuck to the tube.

2

Hey,
try this.

#define AUTO_DISABLE
#define DEBUG_DISPLAY

using UnityEngine;

[RequireComponent (typeof (Rigidbody))]
[RequireComponent (typeof (Collider))]
public class Sticky : MonoBehaviour
{
	[Tooltip ("Surface Rigidbody to Stick To.")]
	[SerializeField] Rigidbody _surfaceBody;
	[Tooltip ("Use Force to attract object to surface.

" +
“Moves position when off.”)]
[SerializeField] bool _useForce;
[SerializeField] float _forceMultiplier = 1f;
[SerializeField] ForceMode _forceMode = ForceMode.VelocityChange;

	Collider _surfaceCollider;

	Rigidbody _rigidbody;
	Collider _collider;

	Vector3 _origin, _destination, _offset, _delta, _target;

	void Awake ()
	{
		_rigidbody = GetComponent<Rigidbody>();
		_collider = GetComponent<Collider>();
		_surfaceCollider = _surfaceBody.GetComponent<Collider>();
	}

	void FixedUpdate ()
	{
		_destination = _surfaceCollider.ClosestPoint(_rigidbody.position);
		_origin = _collider.ClosestPoint(_destination);
		_delta = _destination - _origin;
		_offset = _origin - _rigidbody.position;
		_target = _destination - _offset;

		if (_useForce)
			_rigidbody.AddForce(_delta * _forceMultiplier, _forceMode);
		else
			_rigidbody.MovePosition(_target);
	}

	#if AUTO_DISABLE
	void OnCollisionEnter (Collision col)
	{
		if (col.rigidbody == _surfaceBody)
			enabled = false;
	}

	void OnCollisionExit (Collision col)
	{
		if (col.rigidbody == _surfaceBody)
			enabled = true;
	}
	#endif

	#if DEBUG_DISPLAY
	void OnDrawGizmos ()
	{
		Gizmos.color = Color.yellow;
		Gizmos.DrawWireSphere(_origin, 0.1f);
		Gizmos.color = Color.cyan;
		Gizmos.DrawWireSphere(_destination, 0.1f);
		Gizmos.color = Color.green;
		Gizmos.DrawRay(_origin, _delta);
		Gizmos.color = Color.red;
		Gizmos.DrawWireSphere(_target, 0.1f);
	}
	#endif
}