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# XMPlaneDotNormal method

Calculates the dot product between the normal vector of a plane and a 3D vector.

## Syntax

```
XMVECTOR XMPlaneDotNormal(
[in] XMVECTOR P,
[in] XMVECTOR V
);

```

## Parameters

P [in]

XMVECTOR describing the plane coefficients (A, B, C, D) for the plane equation

```
XMVECTOR vectorOut;

vectorOut.x = P.x * V.x + P.y * V.y + P.z * V.z;
vectorOut.y = P.x * V.x + P.y * V.y + P.z * V.z;
vectorOut.z = P.x * V.x + P.y * V.y + P.z * V.z;
vectorOut.w = P.x * V.x + P.y * V.y + P.z * V.z;

return vectorOut;

```
.
V [in]

3D vector to use in the dot product. The w component of V is always treated as if is 0.0f.

## Return value

Returns the dot product between the normal vector of the plane and V replicated into each of the four components of the returned XMVECTOR.

## Remarks

This function is useful for calculating the angle between the normal vector of the plane, and another normal vector. The following pseudocode demonstrates the operation of the function.

`Ax+By+Cz+D=0`

### Platform Requirements

Microsoft Visual Studio 2010 or Microsoft Visual Studio 2012 with the Windows SDK for Windows 8. Supported for Win32 desktop apps, Windows Store apps, and Windows Phone 8 apps.

## Requirements

 Namespace Use DirectX. DirectXMath.h

## See also

DirectXMath Library Plane Functions

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