A two-dimensional area is defined by the TQ3Area data type.
typedef struct TQ3Area {
TQ3Point2D min;
TQ3Point2D max;
} TQ3Area;
A plane equation is defined by the TQ3PlaneEquation data type.
typedef struct TQ3PlaneEquation {
TQ3Vector3D normal;
float constant;
} TQ3PlaneEquation;