# Plane > Representation of a plane in 3D space. ## Definition * **Type:** Struct * **Namespace:** [UnityEngine](/engine/6000.5/script-reference/unityengine.md) * **Assembly:** UnityEngine.CoreModule * **Implements:** [IEquatable\](https://learn.microsoft.com/dotnet/api/system.iequatable-1), [IFormattable](https://learn.microsoft.com/dotnet/api/system.iformattable) ```csharp public struct Plane : IEquatable, IFormattable ``` ## Remarks A plane is an infinitely large, flat surface that exists in 3D space and divides the space into two halves known as *half-spaces*. It is easy to determine which of the two half-spaces a particular point is in and also how far the point is from the plane. Walls, floors and other flat surfaces are common in games, so a plane is sometimes useful for mathematical calculations with these objects. Also, there are cases where a real surface does not exist but it is useful to imagine that one is there. For example, in sports, a goal line or out-of-bounds line is often assumed to extend into the air, effectively defining a plane. When a plane passes through the \<0,0,0> point in world space, it is defined simply by a normal vector that determines which way it faces. It is easy to visualise this if you imagine looking at the plane edge-on. ![PlaneNormalOrigin (Plane)](/api/media?file=/engine/6000.5/media/images/PlaneNormalOrigin.png) In the previous image a plane is represented as a diagonal red line with the equation x = y passing through the origin point \<0,0,0> in world space. A second line representing a normal vector with a positive y component indicates which direction the plane faces. Note that the side from which the normal vector points is important since it is used to identify which half-space a point is in (ie, on the positive or "normal" side of the plane or the other side). When the plane doesn't pass through \<0,0,0> it can be defined by the normal vector along with a distance from \<0,0,0> ![PlaneNormalOffset (Plane)](/api/media?file=/engine/6000.5/media/images/PlaneNormalOffset.png) In the previous image a plane is represented as a diagonal red line which passes through -2, 0, offset rather than the origin point \<0,0,0>. A second line representing a normal vector with a positive y component indicates which direction the plane faces. A third dotted line defines the distance between the plane and the origin point. A plane can also be defined by the three corner points of a triangle that lies within the plane. In this case, the normal vector points toward you if the corner points go around clockwise as you look at the triangle face-on. ![Plane3Points (Plane)](/api/media?file=/engine/6000.5/media/images/Plane3Points.png). In the previous image a triangle is defined by points A in the bottom left, B at the top, and C at the bottom right. An arrow indicates the plane this triangle lies on as facing towards the viewer. ## Constructors | Constructor | Description | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------- | | [Plane(UnityEngine.Vector3,System.Single)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-float\)) | Creates a plane. | | [Plane(UnityEngine.Vector3,UnityEngine.Vector3)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-vector3\)) | Creates a plane. | | [Plane(UnityEngine.Vector3,UnityEngine.Vector3,UnityEngine.Vector3)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-vector3-vector3\)) | Creates a plane. | | [Plane(UnityEngine.Vector3@,System.Single)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-float\)) | Creates a plane. | | [Plane(UnityEngine.Vector3@,UnityEngine.Vector3@)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-vector3\)) | Creates a plane. | | [Plane(UnityEngine.Vector3@,UnityEngine.Vector3@,UnityEngine.Vector3@)](/engine/6000.5/script-reference/unityengine/plane/ctor.md#plane\(vector3-vector3-vector3\)) | Creates a plane. | ## Properties | Property | Description | | ------------------------------------------------------------------------- | ----------------------------------------------------------------------------- | | [distance](/engine/6000.5/script-reference/unityengine/plane/distance.md) | The distance measured from the Plane to the origin, along the Plane's normal. | | [flipped](/engine/6000.5/script-reference/unityengine/plane/flipped.md) | Returns a copy of the plane that faces in the opposite direction. | | [normal](/engine/6000.5/script-reference/unityengine/plane/normal.md) | Normal vector of the plane. | ## Methods | Method | Description | | ------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- | | [ClosestPointOnPlane](/engine/6000.5/script-reference/unityengine/plane/closestpointonplane.md) | For a given `point` returns the closest point on the plane. | | [Flip](/engine/6000.5/script-reference/unityengine/plane/flip.md) | Makes the plane face in the opposite direction. | | [GetDistanceToPoint](/engine/6000.5/script-reference/unityengine/plane/getdistancetopoint.md) | Returns a signed distance from plane to point. | | [GetSide](/engine/6000.5/script-reference/unityengine/plane/getside.md) | Is a point on the positive side of the plane? | | [Raycast](/engine/6000.5/script-reference/unityengine/plane/raycast.md) | Intersects a ray with the plane. | | [SameSide](/engine/6000.5/script-reference/unityengine/plane/sameside.md) | Are two points on the same side of the plane? | | [Set3Points](/engine/6000.5/script-reference/unityengine/plane/set3points.md) | Sets a plane using three points that lie within it. The points go around clockwise as you look down on the top surface of the plane. | | [SetNormalAndPosition](/engine/6000.5/script-reference/unityengine/plane/setnormalandposition.md) | Sets a plane using a point that lies within it along with a normal to orient it. | | [Translate](/engine/6000.5/script-reference/unityengine/plane/translate.md) | Moves the plane in space by the `translation` vector. | ## Static Methods | Method | Description | | --------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | | [Translate](/engine/6000.5/script-reference/unityengine/plane/translate.md) | Returns a copy of the given plane that is moved in space by the given `translation`. |