Can somebody please guide me how the values of $x_{p}$ and $y_{p}$ in case of oblique parallel projection is equal to:
$$\begin{aligned} x_{p} &= x + L \cos (\phi) \\ y_{p} &= y + L \sin (\phi)\end{aligned}$$
This is mentioned in slide 50 of Three Dimensional Viewing [PDF]. I have studied that oblique projection is the sum of orthogonal and shear. Orthogonal is same as $x$ but i cant understand how we got $L \cos(\phi)$. I would be glad to hear from some body in this regard.
I have found answer to this Question at: http://www.thephysicsforum.com/mathematics/5760-problem-oblique-projection-derivation.html
Zulfi.