Orbit Paths in Unity: Understanding Ellipses

[@GeorgTheGr8]

using System.Collections; using System.Collections.Generic; using UnityEngine; [RequireComponent(typeof(LineRenderer))] public class Ellipse : MonoBehaviour { LineRenderer lr; [Range(3,36)] public int segments; public float xAxis = 5f; public float yAxis = 3f; void Awake() { lr = GetComponent(); CalculateEllipse(); } void CalculateEllipse() { Vector3[] points = new Vector3[segments + 1]; for (int i = 0; i < segments; i++) { float angle = ((float)i / (float)segments) * 360 * Mathf.Deg2Rad; float x = Mathf.Sin(angle) * xAxis; float y = Mathf.Cos(angle) * yAxis; points [i] = new Vector3(x, y, 0f); } points [segments] = points [0]; lr.positionCount = segments + 1; lr.SetPositions (points); } void OnValidate() { if (Application.isPlaying) CalculateEllipse(); } } You're welcome! :)

[@Max29847]

god

[@HadiNauf]

very cool

[@louismarriott4564]

Thanks a lot for this tutorial! I combined this with a lot of maths to generate ellipses rotated around a focii for the orbits of planets :D

[@HadiNauf]

hi, I tried this on my planet game object, so it will look like it has an orbital line around the sun. it works, but when i move object. the position of the orbital line does not move with the object being moved. i tried inserting the script into the game object, but still getting the same problem

[@torktumlarn1364]

why dont you put the code in the description??? D:

[@meh536]

So you watch it and learn something instead of just copying the code

[@beastbomber2316]

@@meh536 ezactly

[@rolfvanderbijl]

For some reason I get a nullrefference error before the script (in Awake) can get the linerenderer component. I solved it by making it public and dragging and dropping the gameObject but isn't there something I did wrong?

[@Rechdan]

Great tutorial! Can't wait for the next video! :D

[@BoardToBitsGames]

Nelson F. Rechdan should be up this time next week!

[@Rechdan]

Excellent, I'm looking forward to make a game in space :D

[@meh536]

Very Nice! Showing all the code and the writing of it really helps noobs like me, instead of just showing random snippets :D

[@NoblesseCheung]

How can I use this ( lr.positionCount & lr.SetPosition) in unity 5.4?

[@bguilleminot]

I'm using Unity 2018.4.19f and I can't add the code line: if (Application.IsPlaying) It triggers the error: "Returns true if the given object is part of the playing world either in any kind of built Player or in Play Mode." Any suggestions?

[@mrroams5812]

My OnValidate is being called before Start and Awake so I am getting a NullReferenceException on the LineRenderer. I'm fairly new to Unity and have never used OnValidate before so I'm wondering why it's working in the video but not for me? In the mean time, I'll just not use OnValidate.

[@ArinA-di6wn]

'UnityEngne.LineRenderer' does not contain a definition for 'positionCount' and no extension method 'positionCount' accepting a first argument of type 'LineRenderer' could be found (are you missing a using directive or an assembly reference?). Why? how to resolve it?

[@lordciciu]

Works with older unity versions too?

[@Dolmek]

[Solved]I've a problem: I'm trying to draw an orbit of one moon around one planet but the orbit is placed around the sun instead of the planet. I placed the moon ad a child of the planet, and the planet is not a child of the sun. Edit: In case some one else need it I solved in this way: where there is in void CalculateElliplse() lr.positionCount = segments + 1; add this line lr.useWorldSpace = false;

[@BoardToBitsGames]

Jonny Othman it’s been awhile since I wrote this, but I believe the orbit is based on a point in world space, not local space, so you’d need to shift it to the planet’s center and calculate the position.

[@Dolmek]

@@BoardToBitsGames I found, it litterally 2 min before read this post. It needed to be add in CalculateElliplse() the line lr.useWorldSpace = false;

[@bhaveshtiwari5783]

You are great

[@joanofarc2276]

awesome!

[@BomTailey]

Hey, really like your video, but just as heads-up in future that your videos are reeeeeeally quiet compared to most videos on youtube - even at 100% YT volume! do a comparison of any other video at 50% volume whilst listening to your own vids at 100% as an example. This isn't much an issue in a quiet environment, but any background noise IRL or from people on voip drowns it out quickly.

[@torktumlarn1364]

i dont see what im doing wrong.... using System.Collections; using System.Collections.Generic; using UnityEngine; [RequireComponent(typeof(LineRenderer))] public class Ellipse : MonoBehaviour { LineRenderer lr; [Range(3, 36)] public int segments; public fload xAxis = 5f; public float yAxis = 3f; void Awake() lr = GetComponent (); CalculateEllipse (); } void CalculateEllipse(){ Vector3[] points = new Vector3[segments + 1]; for (int i = 0; i < segments; i++) { float angle = ((float)i / (float)segments) * 360 * Mathf.Deg2Rad; float x = Mathf.Sin (angle) * xAxis; float y = Mathf.Cos (angle) * yAxis; points[i] = new Vector3(x, y, 0f); } points[segments] = points [0]; LineRenderer.positionCount = segments + 1; LineRenderer.SetPositions (points); } void OnValidate(){ CalculateEllipse (); } }

[@MrKrystian010]

first thing first you should change LineRenderer.positionCount = segments + 1; LineRenderer.SetPositions (points); to lr.positionCount = segments + 1; lr.SetPositions(points);

[@torktumlarn1364]

i had it set to that i just changed it to see if that was it

[@MrKrystian010]

ok so try this, this should work just paste this correctly under: points[segments] = points[0]; and this should work correctly from now on :) lr.positionCount = segments + 1; lr.SetPositions (points); } void OnValidate() { if (Application.isPlaying && lr != null) { CalculateEllipse(); } } }

[@torktumlarn1364]

can you just type copy past your hole code here it dosent seem to work for me i dont know why

[@MrKrystian010]

Sure here you go, I hope it'll work for you :) using UnityEngine; [RequireComponent(typeof(LineRenderer))] public class EllipseRenderer : MonoBehaviour { LineRenderer lr; [Range(3, 36)] public int segments; public fload xAxis = 5f; public float yAxis = 3f; void Awake() { lr = GetComponent(); CalculateEllipse(); } void CalculateEllipse() { Vector3[] points = new Vector3[segments + 1]; for (int i = 0; i < segments; i++) { float angle = ((float)i / (float)segments) * 360 * Mathf.Deg2Rad; float x = Mathf.Sin (angle) * xAxis; float y = Mathf.Cos (angle) * Axis; points[i] = new Vector3(x, y, 0f); } points[segments] = points[0]; lr.positionCount = segments + 1; lr.SetPositions(points); } void OnValidate() { if (Application.isPlaying && lr != null) { CalculateEllipse(); } } }

[@a_soulspark]

I'd like to be a patron but I have no money :(

[@BoardToBitsGames]

+Pedro Brito no worries! As long as you're watching and learning something, I'm good!

[@MaxStranger7]

It looks like your formula is a bit wrong, doesn't it? en.wikipedia.org/wiki/Parametric_equation

[@a_soulspark]

"Understandfing Ellipses"?

[@BoardToBitsGames]

+Pedro Brito its German, I think XD

[@jonjimihendrix]

"We're making video games here, so we can ignore physics." 😃🙃😃

[@VR360TV]

Another video that does not contain the script in the description, what a waist of time. it would take you 2 seconds to past the script in the description...

[@thetruemystic_]

Or actually watch the video, learn how it works instead of just wanting to grab and go. You've got a lot of learning to do.