Visual Basic como detectar colisão 3D num ponto?

[Cambalinho]

eu tenho 1 função para detectar a colisão 3D:
 

Private Function IsCollision3D(ObjectPosition1 As Position3D, ObjectSize1 As Size3D, ObjectPosition2 As Position3D, ObjectSize2 As Size3D)
  IsCollision3D = ((ObjectPosition1.X <= (ObjectPosition2.X + ObjectSize2.Width)) And ((ObjectPosition1.X + ObjectSize1.Width) >= ObjectPosition2.X) And (ObjectPosition1.Y <= (ObjectPosition2.Y + ObjectSize2.Height)) And ((ObjectPosition1.Y + ObjectSize1.Height) >= ObjectPosition2.Y) And (ObjectPosition1.Z <= (ObjectPosition2.Z + ObjectSize2.ZDepth)) And ((ObjectPosition1.Z + ObjectSize1.ZDepth) >= ObjectPosition2.Z))
End Function

e parece funcionar bem.
a partir desta função eu criei 1 função para detectar se um ponto esta dentro da camera:
 

Private Function IsCollisionVertice3D(Vertice1 As Position3D, ObjectPosition2 As Position3D, ObjectSize2 As Size3D)
  IsCollisionVertice3D = ((Vertice1.X <= (ObjectPosition2.X + ObjectSize2.Width)) And ((Vertice1.X) >= ObjectPosition2.X) And (Vertice1.Y <= (ObjectPosition2.Y + ObjectSize2.Height)) And ((Vertice1.Y) >= ObjectPosition2.Y) And (Vertice1.Z <= (ObjectPosition2.Z + ObjectSize2.ZDepth)) And ((Vertice1.Z) >= ObjectPosition2.Z))
End Function

As funções IsCollisionVertice3D() e IsCollision3D() estão correctas?

Private Type Position3D
    X As Double
    Y As Double
    Z As Double
End Type

Private Type Size3D
    width As Double
    height As Double
    ZDepth As Double
End Type