Version: 2022.3
LanguageEnglish
• C#

# GeometryUtility.TryCreatePlaneFromPolygon

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## Declaration

public static bool TryCreatePlaneFromPolygon(Vector3[] vertices, out Plane plane);

### Parameters

 vertices An array of vertex positions that define the shape of a polygon. plane A valid plane that goes through the vertices.

### Returns

bool Returns true on success, false if Unity did not create a plane from the vertices.

### Description

GeometryUtility.TryCreatePlaneFromPolygon creates a plane from the given list of `vertices` that define the polygon, as long as they do not characterize a straight line or zero area.

There must be at least three vertices to create the plane; zero, one or two vertices cause `false` to return with no plane. This works for concave polygons and polygons with multiple aligned vertices, but not for self-intersecting polygons.

```using System.Collections;
using System.Collections.Generic;
using UnityEngine;// GeometryUtility.TryCreatePlaneFromPolygon - example// Attempt to draw a plane through selected positions.
// Seven positions are generated close to the origin. Each position
// will be in a random +/-1 xz area and random -0.5/0.5 y height.
// Use these random positions for the array of vertices.
// A plane is defined with the new positions. The plane is displayed
// using a square Scene example.public class Example : MonoBehaviour
{
private Vector3[] positions;
private GameObject[] gameObjects;
private int count = 7;
private float timer = 999999f;
private Vector3 position;    void Awake()
{
// Generate an array of GameObjects.  Use these to show where the
// positions are based.
gameObjects = new GameObject[count];
for (int i = 0; i < count; i++)
{
gameObjects[i] = GameObject.CreatePrimitive(PrimitiveType.Cube);
gameObjects[i].transform.localScale = new Vector3(0.1f, 0.1f, 0.1f);
gameObjects[i].name = "GO" + i.ToString();
}
positions = new Vector3[count];        // Place the Camera in a sensible location.
Camera.main.transform.position = new Vector3(2.0f, 1.4f, 2.0f);
Camera.main.transform.localEulerAngles = new Vector3(26.0f, -135.0f, 0.0f);
}    private Plane plane;
void Update()
{
// Compute positions of the 7 positions.
if (timer > 5.0f) // True in first call.
{
// Generate an array of positions.
MovePositions(count);            // Now find a plane passing through the positions.
GeometryUtility.TryCreatePlaneFromPolygon(positions, out plane);            timer = 0.0f;
}        DrawPlane(Vector3.zero, plane.normal);
timer += Time.deltaTime;
}    // Move the positions.
void MovePositions(int count)
{
for (int i = 0; i < count; i++)
{
positions[i] = new Vector3(Random.Range(-1.0f, 1.0f), Random.Range(-0.5f, 0.5f), Random.Range(-1.0f, 1.0f));
gameObjects[i].transform.position = positions[i];
}
}    // Generate and display a square that passes through the positions.
// This only works in the Scene view.
void DrawPlane(Vector3 position, Vector3 normal)
{
Vector3 v3;        if (normal.normalized != Vector3.forward)
{
v3 = Vector3.Cross(normal, Vector3.forward).normalized * normal.magnitude;
}
else
{
v3 = Vector3.Cross(normal, Vector3.up).normalized * normal.magnitude;
}        // View the square and normal.
Vector3 corner0 = position + v3;
Vector3 corner2 = position - v3;
Quaternion q = Quaternion.AngleAxis(90.0f, normal);
v3 = q * v3;
Vector3 corner1 = position + v3;
Vector3 corner3 = position - v3;        Debug.DrawLine(corner0, corner2, Color.yellow);
Debug.DrawLine(corner1, corner3, Color.yellow);
Debug.DrawLine(corner0, corner1, Color.yellow);
Debug.DrawLine(corner1, corner2, Color.yellow);
Debug.DrawLine(corner2, corner3, Color.yellow);
Debug.DrawLine(corner3, corner0, Color.yellow);
Debug.DrawRay(position, normal, Color.green);        // Draw lines between the positions.
for (int i = 1; i < count; i++)
{
Debug.DrawLine(positions[i], positions[i - 1], Color.blue);
}
Debug.DrawLine(positions[0], positions[count - 1], Color.blue);
}
}
```