unity 3d drawing on a canvas

The unity line renderer, helps y'all render lines, circles, and other shapes using curves. Also equally some coordinate points in unity so that you lot tin create any sort of curves. You lot can draw color lines in second to help you lot with raycasts or just draw laser beams betwixt 2 points or objects.

This volition be rendered on run time using a line renderer component in unity. Line renderers are useful for cartoon paths in your games.

For example a awarding of line renderers are in the famous game Aroused Birds.

Where a path is fatigued by dragging on a mobile screen.

Line renderer tin can also assist in targetting systems where you desire to describe a raycast of where a bullet might shoot to in a offset person game.

The unity line renderer component can also exist used in building basic drawing apps using the unity engine.

All these applications make line renderers a really important thing to learn in unity.

In this tutorial I will be going over a few principles. Drawing a unity line renderer between a mouse / screen tap, dragging it and drawing it on your scene.

Nosotros will also await at drawing a line renderer between ii game objects.

Dotted lines is also something people are quite interested in and I will look at how we can draw a unity 2d line renderer which can give us a dotted line.

Let's get started on this unity 2d line renderer tutorial, so to start I'm going to create a basic unity project which we can experiment with.

Creating our unity second line renderer project

Start off by opening unity hub. Create a new 2d projection called unity second line renderer. Similar beneath:

With a new bare projection. We want to start by just setting up some basic game objects. So that we can just become to the part of but drawing a basic line renderer.

Create a empty game object. Correct click in the bureaucracy and create a empty game object like below.

Next create a new c# script and call it unity line renderer exam. Like below.

Creating a basic unity add line renderer by script using c#

Let u.s. a construct a basic line renderer script.

                      LineRenderer l = gameObject.AddComponent<LineRenderer>();                  List<Vector3> pos = new List<Vector3>();         pos.Add(new Vector3(0, 0));         pos.Add together(new Vector3(10, 10));         l.startWidth = 1f;         l.endWidth = 1f;         l.SetPositions(pos.ToArray());         50.useWorldSpace = true;        

This code will produce a line similar this.

Allow's at present try do something a piffling more than complicated. Let's create a triangle with the renderer.

To do this we need the first width to be 0 and the end width to exist a larger number. Also allow'due south alter our positions.

LineRenderer l = gameObject.AddComponent();

                      List<Vector3> pos = new List<Vector3>();     pos.Add(new Vector3(0, 5));     pos.Add together(new Vector3(0, -ten));     l.startWidth = 0f;     50.endWidth = 15f;     fifty.SetPositions(pos.ToArray());     fifty.useWorldSpace = true;        

So let'south only walk through this code quick. So we create 2 positions we also create start and end widths.

Where the point which makes the tiptop of the triangle beingness a width of merely 0 and the bottom portion being 15.

Let'due south make a square line renderer.

This should exist similar to the triangle shape. Except we will make our 0 width xv to lucifer the bottom. And so here is the code.

                      LineRenderer 50 = gameObject.AddComponent<LineRenderer>();                  Listing<Vector3> pos = new List<Vector3>();         pos.Add(new Vector3(0, five));         pos.Add together(new Vector3(0, -10));         l.startWidth = 15f;         l.endWidth = 15f;         l.SetPositions(pos.ToArray());         l.useWorldSpace = true;        

Allow's now expect at how we can exercise something somewhat more advanced permit u.s. try create a circle. For this we going to use a few basic mathematics functions to apply pi and draw points.

                      for (int i = 0; i < pointcounter; i++)         {             var radian = Mathf.Deg2Rad * (i * 360f / segments);             points[i] = new Vector3(Mathf.Sin(radian) * radius, Mathf.Cos(radian) * radius,0);         }        

So as you can see you can create a whole lot of different shapes using a line renderer. This tin can give you a lot of liberty to generate these shapes on the wing at run time in your games.

Let us now wait at how we tin color our line renderer.

Unity line renderer color changes

For demonstrating color in our renderer we will go back to using a our square shape.

Let's create ane solid color for our line to do that add together these 2 lines to your lawmaking.

                      l.startColor = Color.reddish;   fifty.endColor = Color.red;        

You need to and then striking run on your project. Y'all will get this pink for now. I will show y'all how to fix it.

To fix this yous need to head over to the correct while running your projection.

Click on that little circumvolve icon and assign a material.

You should at present take this where y'all color is correct.

Let'due south create a slope for our line renderer.

Alter your code to have these colors.

                      l.startColor = Color.red;     fifty.endColor = Colour.white;        

Follow the same steps from earlier and you should at present become a square that looks like this.

This is now all good and well if we simply need ii colors. Let's look at using a multiple colour slope.

Modify your code to apply this instead.

          Gradient g = new Slope();          bladder alpha = 1.0f;          g.SetKeys(             new GradientColorKey[] { new GradientColorKey(Color.dark-green, 0.0f), new GradientColorKey(Color.red, 0.5f), new GradientColorKey(Colour.blue, i.0f) },             new GradientAlphaKey[] { new GradientAlphaKey(alpha,0.0f), new GradientAlphaKey(alpha, 0.5f), new GradientAlphaKey(alpha, one.0f) }         );         l.colorGradient = 1000;        

So how this code works is we outset define a new gradient object. We have a alpha of 1.0 so we have total opacity. So we need to add slope color keys for each color we desire in our gradient.

And then our gradient key has two values, i is the color the other is a time value.

The time value determines how far our slope will stretch here are two examples of what the above code would look like vs the same lawmaking with different time values.

The code that produces the in a higher place is this gradient color keys.

          new GradientColorKey(Color.greenish, 0.0f), new GradientColorKey(Colour.red, 0.2f), new GradientColorKey(Color.blue, 1.0f)        

And then as you tin can see the change to 0.2f on the red calibration makes our green part of our gradient shorter, because our light-green is from 0 to 0.2f.

I think we have now covered a lot on gradients with line renderers and ways to colour your line renderer.

Also if you lot wanted to arrange transparency of your line renderer you lot would exist able to do it past changing that blastoff value.

Let's now look how we can draw a line renderer between two game objects.

Unity line renderer between two gameobjects

For this section of the tutorial we desire to become and create 2 cubes. We will then create a line renderer which will depict between these two game objects. And then become ahead in your projection and right click in your hierarchy and create two cubes.

Once done click on this 2d button to switch into 3d view.

Then motility your cubes then they are somewhat autonomously in your scene similar the below screenshot.

Allow usa likewise add a directional light so that our scene is more lit up.

You lot should now accept something similar this.

Finally to get our photographic camera into 3d view nosotros need to click on our chief camera and modify this settings.

To make your camera marshal to your view you demand to click on align to view in the card similar this.

And so if you striking play on your scene you lot will now end up with your two cubes in your scene in 3d perspective view.

Allow united states now change our code so we tin describe between two game objects.

          using System.Collections; using Organization.Collections.Generic; using UnityEngine;  public form UnityLineRendererTest : MonoBehaviour {     // Start is chosen earlier the first frame update     public GameObject go1;     public GameObject go2;     void Start()     {         LineRenderer 50 = gameObject.AddComponent<LineRenderer>();          List<Vector3> pos = new List<Vector3>();         pos.Add(go1.transform.position);         pos.Add together(go2.transform.position);         l.startWidth = 0.1f;         50.endWidth = 0.1f;         50.SetPositions(pos.ToArray());         l.useWorldSpace = true;       }     }                  

Once you accept updated your code to this. Go ahead and drag your two cubes into the game object slots like this.

You lot should at present cease up with something like this.

Let'south move our code into our update method now so we tin run into how we tin can morph our line renderer past moving our cubes around the scene. So update your code to this.

          using System.Collections; using System.Collections.Generic; using UnityEngine;  public class UnityLineRendererTest : MonoBehaviour {     // Start is chosen before the commencement frame update     public GameObject go1;     public GameObject go2;     LineRenderer fifty;     void Commencement()     {         50 = gameObject.AddComponent<LineRenderer>();      }        // Update is called one time per frame     void Update()     {         List<Vector3> pos = new List<Vector3>();         pos.Add(go1.transform.position);         pos.Add together(go2.transform.position);         l.startWidth = 0.1f;         fifty.endWidth = 0.1f;         l.SetPositions(pos.ToArray());         l.useWorldSpace = truthful;     } }                  

You should at present be able to do this when yous run your project.

That pretty much sums up how you tin can draw a line renderer between two objects in unity likewise as move it around and alter it.

Unity line renderer performance

Permit's talk about performance. Line renderers generally doesn't take a very high performance cost, simply make certain to non over use them.

Also when using them brand certain to have a good clean upwards strategy or pooling or re use strategy and then that you don't continue creating new renderers.

Using best practices for cleaning upwardly objects is e'er advise in unity. So make sure to write sound lawmaking which will help you clean up after yourself.

We take at present done some line renderers between 2 points, between 2 gameobjects, nosotros take looked at different shapes and line renderer coloring.

Permit'due south look at something a fiddling more avant-garde. Allow us try and render a curve.

Frequently asked questions

What is line renderer in unity?

A line renderer in unity is a object which allows you to describe lines. Using multiple points, and then with a line renderer you can depict any type of object if you provide plenty points to construct information technology. Line renderers are useful for trails for aiming.

How do you draw a line in unity?

You lot more often than not would use a line renderer to draw any lines in unity.

How do you brand a laser in unity?

Depending on how basic yous want to go, you tin use a line renderer to describe your lazer beam across the co ordinates of your ray bandage. If yous want something more than consequence rich yous may want to use a particle effect.

Final words

Cheers for following this tutorial on line rendering in unity 2d and 3d. If you liked this tutorial please share it on social media and consider subscribing to my youtube channel hither: https://world wide web.youtube.com/aqueduct/UC1i4hf14VYxV14h6MsPX0Yw

I take also a bunch of other tutorials on game evolution in full general. So feel free to cheque out some of those tutorials and articles from this list.

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Source: https://generalistprogrammer.com/unity/unity-line-renderer-tutorial/

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