Imports System

Imports System.Math

Public Module Module1

    Dim d1() As Double

    Dim d2() As Double

    Dim pipe_end() As Double

    Dim pipe1_end() As Double

    Dim pipe2_end() As Double

    Dim difference() As Double

    Dim t As Double

    Dim s As Double

    Dim point1() As Double

    Dim point2() As Double

    Dim intersection_angle As Double

    Dim len1 As Double

    Dim len2 As Double

    Dim ext1() As Double

    Dim ext2() As Double

    Public Function is_origin(pipe1, pipe2)

        d1 = {pipe1(3),pipe1(4),pipe1(5)}

        d2 = {pipe2(3),pipe2(4),pipe2(5)}

        For i = 0 To d1.Length - 1

            If d1(i) = 0 Then 

                d1(i) = 1E-5

            End If

        Next

        For i = 0 To d2.Length - 1

            If d2(i) = 0 Then 

                d2(i) = 1E-5

            End If

        Next

        If pipe1(7)=0 Then

            pipe1_end = {pipe1(0),pipe1(1),pipe1(2)}

        Else

            pipe1_end = {pipe1(0)+pipe1(3),pipe1(1)+pipe1(4),pipe1(2)+pipe1(5)}

        End If

        If pipe2(7)=0 Then

            pipe2_end = {pipe2(0),pipe2(1),pipe2(2)}

        Else

            pipe2_end = {pipe2(0)+pipe2(3),pipe2(1)+pipe2(4),pipe2(2)+pipe2(5)}

        End If

        Return pipe1_end

        Return pipe2_end

    End Function

    Public Function intersect3D(pipe1, pipe2)

        pipe_end = is_origin(pipe1,pipe2)

        difference = {pipe2(0)-pipe1(0),pipe2(1)-pipe1(1),pipe2(2)-pipe1(2)}

        If pipe1(3) = 0 And pipe2(3) = 0 Then

            If d2(2)*d1(1)-d1(2)*d2(1) = 0 Then

                d1(1) = d1(1) + 1E-9

            End If

            s = -1*(difference(2)*d1(1)-d1(2)*difference(1))/(d2(2)*d1(1)-d1(2)*d2(1))

            t = (difference(1)-d2(1)*s)/d1(1)

        ElseIf pipe1(4) = 0 And pipe2(4) = 0 Then

            If d2(2)*d1(0)-d1(2)*d2(0) = 0 Then

                d1(1) = d1(1) + 1E-9

            End If

            s = -1*(d1(0)*difference(2)-d1(2)*difference(0))/(d2(2)*d1(0)-d1(2)*d2(0))

            t = (difference(0)-d2(0)*s)/d1(0)

        ElseIf pipe1(5) = 0 And pipe2(5) = 0 Then

            If d2(1)*d1(0)-d1(1)*d2(0) = 0 Then

                d1(0) = d1(0) + 1E-9

            End If

            s = -1*(difference(1)*d1(0)-d1(1)*difference(0))/(d2(1)*d1(0)-d1(1)*d2(0))

            t = (difference(10)-d2(0)*s)/d1(0)

        Else

            s = -1*(difference(2)*d1(1)-d1(2)*difference(1))/(d2(2)*d1(1)-d1(2)*d2(1))

            t = (difference(1)-d2(1)*s)/d1(1)

        End If

        point1 = {pipe1(0)+t*d1(0),pipe1(1)+t*d1(1),pipe1(2)+t*d1(2)}

        point2 = {pipe2(0)+s*d2(0),pipe2(1)+s*d2(1),pipe2(2)+s*d2(2)}

        intersection_angle = math.acos((d1(0)*d2(0)+d1(1)*d2(1)+d1(2)*d2(2))/((((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5)*(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5)))

​

        If ((point1(0)-point2(0))^2+(point1(1)-point2(1))^2+(point1(2)-point2(2))^2)^0.5 < 0.01 Then

            len1 = ((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5 + ((pipe1_end(0)-point1(0))^2+(pipe1_end(1)-point1(1))^2+(pipe1_end(2)-point1(2))^2)^0.5 + pipe1(6)*Math.tan(intersection_angle/2)

            len2 = ((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5 + ((pipe2_end(0)-point1(0))^2+(pipe2_end(1)-point1(1))^2+(pipe2_end(2)-point1(2))^2)^0.5 + pipe2(6)*Math.tan(intersection_angle/2)

            ext1 = {pipe1(3)-len1*pipe1(3)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5),pipe1(4)-len1*pipe1(4)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5),pipe1(5)-len1*pipe1(5)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5),len1*pipe1(3)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5)-pipe1(3),len1*pipe1(4)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5)-pipe1(4),len1*pipe1(5)/(((d1(0)^2)+(d1(1)^2)+(d1(2)^2))^0.5)-pipe1(5)}

            ext2 = {pipe2(3)-len2*pipe2(3)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5),pipe2(4)-len2*pipe2(4)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5),pipe2(5)-len2*pipe2(5)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5),len2*pipe2(3)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5)-pipe2(3),len2*pipe2(4)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5)-pipe2(4),len2*pipe2(5)/(((d2(0)^2)+(d2(1)^2)+(d2(2)^2))^0.5)-pipe2(5)}

            For i As Integer = 0 To 2

                If pipe1_end(i) <> pipe1(i) Then

                    ext1(i) = 0

                ElseIf pipe2_end(i) <> pipe2(i) Then

                    ext2(i) = 0

                End If

            Next

        Else

            Return Nothing

        End If

    End Function

    Public Sub Main()

        Dim pipe1() As Double = {-1975.9373,333.457,-6369.0332,0,-95.9239,95.9239,2.54,1}   

        Dim pipe2() As Double = {-1975.9373,238.505,-6275.4558,0,0,114.4948,2.54,0}

        intersect3D(pipe1,pipe2)

    End Sub

End Module