From Solid Graphics Wiki
The Plane class represents a plane. The plane is specified by the plane's normal vector and it's distance from the coordinate system origin (by the offset field). The Plane class uses float precision.
Constructors
Default Plane class constructor does not initialize the plane fields to any value. This is on purpose for performance reasons. Other class costructors allow to initialize the Plane object from other plane, vector and a offset, or four float valuse..
Fields
Field name
 Type
 Description

x
 float
 (inherited from the Vector class) the X coordinate of planes normal vector

y
 float
 (inherited from the Vector class) the Y coordinate of planes normal vector

z
 float
 (inherited from the Vector class) the Z coordinate of planes normal vector

offset
 float
 plane's distance value from the coordinate system origin (0, 0, 0). (The offset represents the distance correctly only if plane's normal vector's length is 1 )

Methods
Create
 Creates the plane from plane normal vector and a point which is part of the plane, or a three points lying in the plane.

RecalculateOffset
 Recalculates the offset field to include specified point.

Normalize
 Scales the plane values so its' normal vector's length is 1.

Scale
 Scales the plane values by specified factor.

Distance
 Returns distance of specified point to the plane.

GetUVVectors
 Returns two nonparallel vectors which lie inside of the plane.

ClosestPlanePoint
 Returns point which lies inside the plane and is closest to the specuified point.

VectorProjection
 Returns vector which is projection of specified vector to the plane's normal vector.

Operators
*
 Returns a plane equal to the plane instance scaled by the operand.

=
 assigns a vector to the plane. The offset field is initialized to value 0.0f.

*=
 Scales the plane by specified operand.

/=
 Divides the vector by specified operand

See Also
SolidKit Library Documentation