How to add inertia damping?

Questions & Answers
1

I have the bellow code witch open-closes a drawer by mouse dragging. How do i add inertia?

Here is the code.

using UnityEngine;
using System.Collections;

public class draw : MonoBehaviour {

	float translate_z;
	float current_z;
	float sensX = 4.0f;

	public bool isDraging;
	public GameObject drawer;

	void Update () {
		if (Input.GetMouseButton (0)) {
			if (!isDraging) {
				RaycastHit hit;
				Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition); 
				if (Physics.Raycast (ray, out hit, 5.0f)) {
					drawer = hit.collider.gameObject;
					current_z = hit.collider.transform.position.z;
					translate_z = current_z;
					Debug.Log (current_z);
					isDraging = true;
				}
			}

			if (isDraging) {
				translate_z += Input.GetAxis ("Mouse Y") * sensX * Time.deltaTime;
				translate_z = Mathf.Clamp (translate_z, -1.25f, 0.0f);
				drawer.transform.localPosition = new Vector3 (0.0f, 0.0f, translate_z);
			}
		} else if (Input.GetMouseButtonUp(0)) {
			isDraging = false;
		}
	}
}
2

This should work, it adds a speed modifier that is increased every frame that the drawer is dragged, and is decreased every frame that it isn’t.

using UnityEngine;
using System.Collections;
 
public class draw : MonoBehaviour {
 
float translate_z;
float current_z;
float sensX = 4.0f;
float currentDragSpeed = 0; // The speed the drawer is being dragged
float maxDragSpeed = 1f; // Change this to the fastest speed you want to be able to drag the drawer at
float accelerationRate = 0.01f;	// Changing this value will affect how quickly the drawer accelerates

public bool isDraging;
public GameObject drawer;

void Update () {
	if (Input.GetMouseButton (0)) {
		if (!isDraging) {
			RaycastHit hit;
			Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition); 
			if (Physics.Raycast (ray, out hit, 5.0f)) {
				drawer = hit.collider.gameObject;
				current_z = hit.collider.transform.position.z;
				translate_z = current_z;
				Debug.Log (current_z);
				isDraging = true;
			}
		}

		if (isDraging) 
		{
			if(currentDragSpeed < maxDragSpeed)	//	While the drawer can accelerate further
			{                 
				currentDragSpeed += accelerationRate;	//	Accelerate
			}
		}
		else
		{
			if(currentDragSpeed > 0)	//	While the drawer is still moving
			{
				currentDragSpeed -= accelerationRate;	//	Decelerate
		}
	}

	translate_z = Input.GetAxis ("Mouse Y") * sensX* currentDragSpeed * Time.deltaTime;
	translate_z = Mathf.Clamp (translate_z, -1.25f, 0.0f);
	drawer.transform.localPosition += new Vector3 (0.0f, 0.0f, translate_z);

	} else if (Input.GetMouseButtonUp(0)) {
             isDraging = false;
		}
    }
}