Unity Script Reference:

Handles.DrawBezier

static function DrawBezier(startPosition: Vector3, endPosition: Vector3, startTangent: Vector3, endTangent: Vector3, color: Color, texture: Texture2D, width: float): void;

static void DrawBezier(Vector3 startPosition, Vector3 endPosition, Vector3 startTangent, Vector3 endTangent, Color color, Texture2D texture, float width);

static def DrawBezier(startPosition as Vector3, endPosition as Vector3, startTangent as Vector3, endTangent as Vector3, color as Color, texture as Texture2D, width as float) as void

Description

Draw textured bezier line through start and end points with the given tangents. To get an anti-aliased effect use a texture that is 1x2 pixels with one transparent white pixel and one opaque white pixel. The bezier curve will be swept using this texture.

Note: Use HandleUtility.GetHandleSize where you might want to have constant screen-sized handles.

Bezier Line in the Scene View.

	// Draws a red bezier curve from (0,0,0) to the transform's position
	
	@CustomEditor (BezierScript)
	class DrawBezierHandle extends Editor {
		
		function OnSceneGUI() {
			var width : float = HandleUtility.GetHandleSize(Vector3.zero) * 0.1;
	    	Handles.DrawBezier(target.transform.position, 
    					Vector3.zero, 
    					Vector3.up, 
    					-Vector3.up,
    					Color.red, 
    					null,
    					width);
	    }
	}

And the script attached to this Handle:

	//BezierScript.js
	
	Debug.Log("I have a bezier curve handle attached!");