P2-5-7 
(a) Depth distance of roof (Point A) 
and vertical wall (Point B) points 
Fig. 4 Concept of depth distance 
(b) Comparison of depth distance 
between overlapping "Fore" sides; 
A on the roof and B on the vertical 
wall (AA' > BB', then A hides B) 
a) Overlap between roof and wall,(points F^^nd V\^) b) Overlap between roofs 
and between walls (points V\( 1 and W 22 ) 
Fig. 5 Hiding and hidden parts using the depth distance 
4 
I 
3 
I 
2 
1 
I 
0 
L 
a) Depth distance of a convex shaped 
building 
b) Depth distance of a concave shaped 
building 
Fig. 6 Depth distance in case of polygon shift