Three Point Perspective

For this demonstration I have chosen an arbitrary placement 
for the Nadir. The further the Nadir is from the subject 
(downward), the less "forced' the perspective will look. "Forced 
Perspective" gives the impression that you are viewing the subject 
through a "fish eye" or "wide angle" lens of a camera. By moving the 
Nadir downward, you will "flatten" the perspective giving the
 impression that you are viewing the subject through a "telephoto" 
or "long" lens.

In Fig. 5 & 6 we will start to construct the secondary features
 of the subject(green dots). The first step will be to establish the 
secondary vertical plane shown in Fig. 5. Then we will construct 
or secondary horizontal plane shown in Fig. 6.

Once we have completed our construction lines we will start to
 "draw" our final black outlines by using Adobe Illustrator's 
"Scissors (C)" tool to cut the construction lines (in the 
location of the green dots) and give them new thickness and 
color attributes. For additional information on this line 
technique go to the "Controlling Line Weights & 
Quality" Adobe Illustrator Tutorial.

Continue the process of cutting the construction lines and
 using Illustrator's "Eyedropper (I)" tool to sample the 
attributes of your other black outlines. As was shown in 
Fig. 7, make your cuts in the location of the green dots.

Now that you have completed the process of cutting out all of the necessary lines in out subject, you can eliminate the distraction of the construction lines. Cut them back using the "Scissors (C)" tool,but keep them handy in the event that you need to change the position of, or add additional lines to the subject.

The last step is to darken the object's construction lines, 
and add weight to all of the exterior and outside 
edge lines, to increase readability Fig. 10. See the 
"Controlling Line Weights & Quality" Adobe 
Illustrator Tutorial for additional information on
 "line" control.