## SIVector3.Dot

### Description

Returns the dot product of this vector and vector v. A dot product is defined as :
X . Y = |X| |Y| cos( theta )
Where theta is the angle between your vectors and |X| is the length of the vector X.

### C# Syntax

    Double SIVector3.Dot( SIVector3 in_pVector );

### Scripting Syntax

    oFloat = SIVector3.Dot( v );

### Return Value

Floating point value (dot product of this vector and vector v).

### Parameters

Parameter | Type | Description
--- | --- | ---
v | SIVector3 | Operand vector

### Examples

#### 1. JScript Example

    x = XSIMath.CreateVector3();
    y = XSIMath.CreateVector3();
    // Example 1: Perpendicular vectors have 0 dot product
    x.Set( 1,0,0 ) ;
    y.Set( 0,1,0 ) ;
    // Output is 0
    Application.LogMessage( x.Dot( y ) ) ;
    // Example 2: Commutative nature of dot product
    x.Set( 2,0,0 ) ;
    y.Set( 1,1,0 ) ;
    // Output is 2 for both
    Application.LogMessage( x.Dot( y ) ) ;
    Application.LogMessage( y.Dot( x ) ) ;
    // Example 3: When angle is zero the value
    // is equal to the lengths multipled
    x.Set( 2,0,0 ) ;
    y.Set( 3,0,0 ) ;
    //Output is 6 for both
    Application.LogMessage( x.Dot( y ) ) ;
    Application.LogMessage( x.length() * y.length() ) ;

#### 2. VBScript Example

    dim v1, v2
    ' Create 3D vectors.
    set v1 = XSIMath.CreateVector3
    set v2 = XSIMath.CreateVector3
    v1.Set 1.0, 0.0, 0.0
    v2.Set 1.0, 1.0, 0.0
    Application.LogMessage v1.Dot( v2 )

### See Also

SIVector3.Angle SIMatrix3 SIMatrix4 SIRotation SITransformation SIQuaternion