# simulate motion parable
**URL:** https://discussions.unity.com/t/simulate-motion-parable/609351
**Category:** Scripting
**Tags:** Scripting
**Created:** [December 17, 2015, 8:47am UTC](https://discussions.unity.com/t/simulate-motion-parable/609351 "2015-12-17T08:47:12Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Bolt](https://discussions.unity.com/u/Bolt)
#### Post date: [December 17, 2015, 8:47am UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/1 "2015-12-17T08:47:12Z")
Hello everyone, I have tried to introduce in html and js equation to simulate the movement of a ball along a parabola with this formula: 1/2 \* g \* (x \* x) / (Vx \* Vx) + Vy / Vx \* x.
X is the horizontal position, G is gravity, Vx is the speed on the X and Vy is the velocity on the Y. This equation works fine but I can not place it in unity. Can you give me a hand?
---
### Author:  [@CloudKid](https://discussions.unity.com/u/CloudKid)
#### Post date: [December 17, 2015, 9:55am UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/2 "2015-12-17T09:55:19Z")
I don’t see where is the problem, just look online how to obtain each parameter. For example x is transform.position.x.
You take g from the rigidBody component (rigidBody.gravity?) and velosity from rigidBody.velosity. By rigid body I mean GetComponent(). If you have no idea what transform/rigidBody is I suggest to google them and learn how do they work
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### Author:  [@Bolt](https://discussions.unity.com/u/Bolt)
#### Post date: [December 17, 2015, 12:04pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/3 "2015-12-17T12:04:42Z")
I followed a tutorial to understand trigonometry. It only works with the courutiner when the play. How can I make it work in the update?
```auto
using UnityEngine;
using System.Collections;
public class ThrowSimulation : MonoBehaviour
{
public Transform Target;
public float firingAngle = 45.0f;
public float gravity = 9.8f;
public Transform Projectile;
private Transform myTransform;
void Awake()
{
myTransform = transform;
}
void Update()
{
SimulateProjectile();
}
void SimulateProjectile()
{
// Short delay added before Projectile is thrown
// Move projectile to the position of throwing object + add some offset if needed.
Projectile.position = myTransform.position + new Vector3(0, 0.0f, 0);
// Calculate distance to target
float target_Distance = Vector3.Distance(Projectile.position, Target.position);
// Calculate the velocity needed to throw the object to the target at specified angle.
float projectile_Velocity = target_Distance / (Mathf.Sin(2 * firingAngle * Mathf.Deg2Rad) / gravity);
// Extract the X Y componenent of the velocity
float Vx = Mathf.Sqrt(projectile_Velocity) * Mathf.Cos(firingAngle * Mathf.Deg2Rad);
float Vy = Mathf.Sqrt(projectile_Velocity) * Mathf.Sin(firingAngle * Mathf.Deg2Rad);
// Calculate flight time.
float flightDuration = target_Distance / Vx;
// Rotate projectile to face the target.
Projectile.rotation = Quaternion.LookRotation(Target.position - Projectile.position);
float elapse_time = 0;
if(elapse_time < flightDuration)
{
Projectile.Translate(0, (Vy - (gravity * elapse_time))*Time.deltaTime , Vx * Time.deltaTime);
// Projectile.Translate(0, (Vy - (gravity )) * elapse_time, Vx * Time.time);
// Projectile.transform.position += new Vector3(0F,( Vy * elapse_time)-gravity , Vx )*Time.time ;
elapse_time += Time.deltaTime;
}
}
}
```
---
### Author:  [@CloudKid](https://discussions.unity.com/u/CloudKid)
#### Post date: [December 17, 2015, 12:09pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/4 "2015-12-17T12:09:26Z")
You have to make “elapse\_time” global and reset it (elapse\_time =0) only when you need to reset your trajectory
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### Author:  [@Bolt](https://discussions.unity.com/u/Bolt)
#### Post date: [December 17, 2015, 12:21pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/5 "2015-12-17T12:21:46Z")
Thanks for the answer. I’m doing this exercise to understand trigonometry in video games. You know you recommend some program or plugin to help me study and understand?
---
### Author:  [@CloudKid](https://discussions.unity.com/u/CloudKid)
#### Post date: [December 17, 2015, 12:43pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/6 "2015-12-17T12:43:53Z")
Try out this chanel [https://www.youtube.com/channel/UCb0DBpjN2lZhJCflvMUCJpw](https://www.youtube.com/channel/UCb0DBpjN2lZhJCflvMUCJpw)
This guy tries to explain trigonometry in Unity
---
### Author:  [@Bolt](https://discussions.unity.com/u/Bolt)
#### Post date: [December 17, 2015, 12:52pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/7 "2015-12-17T12:52:39Z")
it is yours? I am following him for some time: D
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### Author:  [@CloudKid](https://discussions.unity.com/u/CloudKid)
#### Post date: [December 17, 2015, 1:34pm UTC](https://discussions.unity.com/t/simulate-motion-parable/609351/8 "2015-12-17T13:34:46Z")
Nope, cool tuts though