>>718507175
If you need straight line, you use ruler. If you need perfect circle, you use circle tool. However if you drawing an illustration of, let's say, car with circular tires and some straight planes, you do construct them to show their ahape but you draw them freehand. Completely oerfect straight lines and circles don't mesh well with the rest of the illustrations. But even then the artist dont draw compketely straight lines or circles in one go. They ibstead convey the illusion of them being straight and circular