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Unity Engine

ProjectOnPlane

Projects a vector onto a plane.
Read time 2 minutesLast updated 6 days ago

Definition

  • Type: Method
  • Namespace: UnityEngine
  • Assembly: UnityEngine.CoreModule

ProjectOnPlane(Vector3, Vector3)

Projects a vector onto a plane.
public static Vector3 ProjectOnPlane(Vector3 vector, Vector3 planeNormal)

Parameters

vector

Vector3
The vector to project on the plane.

planeNormal

Vector3
The normal which defines the plane to project on.

Returns

Type

Description

Vector3The vector that results from projection of 
vector
on the plane.

Remarks

This method resolves the input vector onto the plane and returns the resulting vector. The new vector is orthogonal to 
planeNormal
and parallel to the plane.
Note that 
planeNormal
does not need to be normalized.
// This example rotates a cube above a tilted plane. As the cube rotates, the cube's position vector is projected onto the plane and rendered as a line. 

using UnityEngine;

public class ProjectOnPlaneExampleUpdate: MonoBehaviour
{
 GameObject groundPlane;
 GameObject rotObject;
 LineRenderer line;


 void Start ()
 {
 // Create the plane
 groundPlane = GameObject.CreatePrimitive(PrimitiveType.Plane);
 groundPlane.transform.Rotate(-30, 10, 0);

 // Create the item to rotate    
 rotObject = GameObject.CreatePrimitive(PrimitiveType.Cube);
 rotObject.transform.position = new Vector3(5,5,0);
 line = rotObject.AddComponent<LineRenderer>();
 }

 void Update()
 {
 // Set the rotation origin
 Vector3 origin = Vector3.zero;

 // Rotate the object above the plane
 rotObject.transform.RotateAround(origin, Vector3.up, 20 * Time.deltaTime);

 // Project the location of the cube onto the plane
 Vector3 projected = Vector3.ProjectOnPlane(rotObject.transform.position, groundPlane.transform.up);

 // Draw the projected vector as a line
 line.SetPosition(0, origin);
 line.SetPosition(1, projected);
 line.startWidth = 0.1f;  

 }
}
Additional Resources: Vector3.Project, Vector3.Reflect.

ProjectOnPlane(Vector3, Vector3)

Projects a vector onto a plane.
public static Vector3 ProjectOnPlane(in Vector3 vector, in Vector3 planeNormal)

Parameters

vector

Vector3
The vector to project on the plane.

planeNormal

Vector3
The normal which defines the plane to project on.

Returns

Type

Description

Vector3The vector that results from projection of 
vector
on the plane.

Remarks

This method resolves the input vector onto the plane and returns the resulting vector. The new vector is orthogonal to 
planeNormal
and parallel to the plane.
Note that 
planeNormal
does not need to be normalized.
// This example rotates a cube above a tilted plane. As the cube rotates, the cube's position vector is projected onto the plane and rendered as a line. 

using UnityEngine;

public class ProjectOnPlaneExampleUpdate: MonoBehaviour
{
 GameObject groundPlane;
 GameObject rotObject;
 LineRenderer line;


 void Start ()
 {
 // Create the plane
 groundPlane = GameObject.CreatePrimitive(PrimitiveType.Plane);
 groundPlane.transform.Rotate(-30, 10, 0);

 // Create the item to rotate    
 rotObject = GameObject.CreatePrimitive(PrimitiveType.Cube);
 rotObject.transform.position = new Vector3(5,5,0);
 line = rotObject.AddComponent<LineRenderer>();
 }

 void Update()
 {
 // Set the rotation origin
 Vector3 origin = Vector3.zero;

 // Rotate the object above the plane
 rotObject.transform.RotateAround(origin, Vector3.up, 20 * Time.deltaTime);

 // Project the location of the cube onto the plane
 Vector3 projected = Vector3.ProjectOnPlane(rotObject.transform.position, groundPlane.transform.up);

 // Draw the projected vector as a line
 line.SetPosition(0, origin);
 line.SetPosition(1, projected);
 line.startWidth = 0.1f;  

 }
}
Additional Resources: Vector3.Project, Vector3.Reflect.