Gizmos.DrawLine

Parameters

Description

Draws a line between two points in the Scene view.

DrawLine is a method used for visual debugging in the Unity Editor. Use DrawLine to render a line segment in the Scene view. DrawLine is versatile and can be used to visualize connections, paths, or boundaries in your scene.

The line is drawn using the current Gizmos color, which can be set using Gizmos.color before calling DrawLine. The line is drawn using the current Gizmos matrix, which can be set using Gizmos.matrix before calling DrawLine.

Typically, you'd use this method within MonoBehaviour.OnDrawGizmos or MonoBehaviour.OnDrawGizmosSelected functions in your MonoBehaviour scripts, or within a method with the DrawGizmo attribute. Like all Gizmos, it's an Editor-only tool and should not be used for game functionality. This method has no effect in the Game view or at runtime. If you want to draw similar shapes at runtime, refer to Debug.DrawLine.

The line respects the 3D space and perspective of the scene, including depth and occlusion by other objects. It also respects the alpha channel of the Gizmos color, allowing for semi-transparent lines as well as the transformation of Gizmos.matrix.

If you need to draw many lines consider the Gizmos.DrawLineList or Gizmos.DrawLineStrip functions which are much faster than repeatedly calling this function to draw lines individually.

using UnityEngine;

public class LineGizmoExample : MonoBehaviour
{
    public Transform endPoint;
    [Range(0f, 1f)]
    public float alpha = 0.75f;

    private void OnDrawGizmos()
    {
        if (endPoint == null) return;

        // Set the color with custom alpha
        Gizmos.color = new Color(1f, 1f, 0f, alpha); // Yellow with custom alpha

        // Draw the line
        Gizmos.DrawLine(transform.position, endPoint.position);

        // Draw spheres at start and end points
        Gizmos.DrawSphere(transform.position, 0.1f);
        Gizmos.DrawSphere(endPoint.position, 0.1f);

        // Calculate and display the midpoint
        Vector3 midpoint = (transform.position + endPoint.position) / 2f;
        Gizmos.color = Color.red;
        Gizmos.DrawSphere(midpoint, 0.15f);

        // Display the distance
        float distance = Vector3.Distance(transform.position, endPoint.position);
        UnityEditor.Handles.Label(midpoint, $"Distance: {distance:F2}");
    }
}

Additional resources: Gizmos.DrawLineList, Gizmos.DrawLineStrip, MonoBehaviour.OnDrawGizmos, MonoBehaviour.OnDrawGizmosSelected, DrawGizmo, Gizmos.color, Gizmos.matrix.