Why does the following code not work?

public float ThetaScale = 0.0001f;
private int Size;
private LineRenderer LineDrawer;
private float Theta = 0f;

void Start ()
  LineDrawer = GetComponent<LineRenderer>();
  LineDrawer.SetWidth(0.1f, 0.1f);
  LineDrawer.material = new Material(Shader.Find("Mobile/Particles/Additive"));
  LineDrawer.SetColors(Color.blue, Color.blue);

void DrawingCircle(float radius)
Theta = 0f;
Size = (int)((1f / ThetaScale) + 1f);
for(int i = 0; i < Size; i++){
    Theta += (2.0f * Mathf.PI * ThetaScale);
    float x = radius * Mathf.Cos(Theta);
    float y = radius * Mathf.Sin(Theta);
    LineDrawer.SetPosition(i, new Vector3(x, y, 0));

void Update ()
    for(int l = 0; l < 3; l++)

I want to plot a multiple circles like that

enter image description here

What's a good way to draw multiple circles?

  • 2
    \$\begingroup\$ What does your current code do, and how does it differ from what you want? \$\endgroup\$ – DMGregory Nov 25 at 23:13
  • \$\begingroup\$ A LineRenderer is a component like any other. You don't need to update it every frame even when nothing changed. \$\endgroup\$ – Philipp Nov 26 at 11:49
  • 1
    \$\begingroup\$ Note also that you are using one render for all three circles but you are overwriting the previous circle each time so you will only ever see the last circle \$\endgroup\$ – Ed Marty Nov 26 at 13:49

I think your confusion comes from a misunderstanding of what the LineRenderer component does.

A LineRenderer isn't a "line drawer". It doesn't draw lines. It visualizes a game object in form of a visible polygon strip in 3d space. Just like a SpriteRenderer visualizes a game object as a sprite or a MeshRenderer visualizes a game object as a 3d mesh.

So when you want 3 separate lines in your game, you need 3 different game objects with a LineRenderer each. When their coordinates don't change, you only need to set them once. It's not necessary to reassign their components in every update.


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