Given two triangles P along with vertices as P1(100,100,50), P2(50,50,50), P3(150,50,50) and q along with vertices as Q1(40,80,60), q2(70,70,50), Q3( 10,75,70), determine that triangle should be painted first by using the scan- line method.

Solution: In the method of scan-line, two triangles P and Q are tested for overlap in xy- plane. After that they are tested for depth overlap. In this matter, there is no overlap in the depth. Although, P and Q have overlap in xy-plane consequently the Q is painted first followed by P.