Task: Find the intersection of a line with a plane





Java: public class LinePlaneIntersection {
    private static class Vector3D {
        private double x, y, z;

        Vector3D(double x, double y, double z) {
            this.x = x;
            this.y = y;
            this.z = z;
        }

        Vector3D plus(Vector3D v) {
            return new Vector3D(x + v.x, y + v.y, z + v.z);
        }

        Vector3D minus(Vector3D v) {
            return new Vector3D(x - v.x, y - v.y, z - v.z);
        }

        Vector3D times(double s) {
            return new Vector3D(s * x, s * y, s * z);
        }

        double dot(Vector3D v) {
            return x * v.x + y * v.y + z * v.z;
        }

        @Override
        public String toString() {
            return String.format("(%f, %f, %f)", x, y, z);
        }
    }

    private static Vector3D intersectPoint(Vector3D rayVector, Vector3D rayPoint, Vector3D planeNormal, Vector3D planePoint) {
        Vector3D diff = rayPoint.minus(planePoint);
        double prod1 = diff.dot(planeNormal);
        double prod2 = rayVector.dot(planeNormal);
        double prod3 = prod1 / prod2;
        return rayPoint.minus(rayVector.times(prod3));
    }

    public static void main(String[] args) {
        Vector3D rv = new Vector3D(0.0, -1.0, -1.0);
        Vector3D rp = new Vector3D(0.0, 0.0, 10.0);
        Vector3D pn = new Vector3D(0.0, 0.0, 1.0);
        Vector3D pp = new Vector3D(0.0, 0.0, 5.0);
        Vector3D ip = intersectPoint(rv, rp, pn, pp);
        System.out.println("The ray intersects the plane at " + ip);
    }
}




VB: Module Module1

    Class Vector3D
        Private ReadOnly x As Double
        Private ReadOnly y As Double
        Private ReadOnly z As Double

        Sub New(nx As Double, ny As Double, nz As Double)
            x = nx
            y = ny
            z = nz
        End Sub

        Public Function Dot(rhs As Vector3D) As Double
            Return x * rhs.x + y * rhs.y + z * rhs.z
        End Function

        Public Shared Operator +(ByVal a As Vector3D, ByVal b As Vector3D) As Vector3D
            Return New Vector3D(a.x + b.x, a.y + b.y, a.z + b.z)
        End Operator

        Public Shared Operator -(ByVal a As Vector3D, ByVal b As Vector3D) As Vector3D
            Return New Vector3D(a.x - b.x, a.y - b.y, a.z - b.z)
        End Operator

        Public Shared Operator *(ByVal a As Vector3D, ByVal b As Double) As Vector3D
            Return New Vector3D(a.x * b, a.y * b, a.z * b)
        End Operator

        Public Overrides Function ToString() As String
            Return String.Format("({0:F}, {1:F}, {2:F})", x, y, z)
        End Function
    End Class

    Function IntersectPoint(rayVector As Vector3D, rayPoint As Vector3D, planeNormal As Vector3D, planePoint As Vector3D) As Vector3D
        Dim diff = rayPoint - planePoint
        Dim prod1 = diff.Dot(planeNormal)
        Dim prod2 = rayVector.Dot(planeNormal)
        Dim prod3 = prod1 / prod2
        Return rayPoint - rayVector * prod3
    End Function

    Sub Main()
        Dim rv = New Vector3D(0.0, -1.0, -1.0)
        Dim rp = New Vector3D(0.0, 0.0, 10.0)
        Dim pn = New Vector3D(0.0, 0.0, 1.0)
        Dim pp = New Vector3D(0.0, 0.0, 5.0)
        Dim ip = IntersectPoint(rv, rp, pn, pp)
        Console.WriteLine("The ray intersects the plane at {0}", ip)
    End Sub

End Module