Vanishing point as the "direction point", as lines having the same directional vector, say "D", will have the same vanishing point. Mathematically, let be a point lying on the image plane, where is the focal length (of the camera associated with the image), and let be the unit vector associated with , where . If we consider a straight line in space with the unit vector and its vanishing point , the unit vector associated with is equal to , assuming both are assumed to point towards the image plane. When the image plane is parallel to two world-coordinate axes, lines parallel
Point-to-Point Protocol daemon also capable of handling Dial-on-demand routing, where pppd sets up a virtual network, captures the packages it receives and establishes a PPP connection and forwards the captured and not-yet transmitted packages over the link. Point-to-Point Protocol daemon PPPD is the Point-to-Point Protocol daemon which is used to manage network connections between two nodes on Unix-like operating systems. It is configured using command-line arguments and configuration files. While it has initially been used to manage only dial-up access, it is also used to manage broadband connections such as DSL, if Point-to-Point Protocol over Ethernet (PPPoE) or Point-to-Point Protocol over ATM (PPPoA)