tailieunhanh - Perspective Drawing Handbook - Phần 5

Tài liệu tham khảo bằng tiếng Anh về hội họa - Perspective Drawing Handbook - Phần 5 | Chapter 11 DETERMINING DEPTHS Finding Center Points By Diagonals The following concept is the basis for most of the aids employed in finding perspective depths The diagonals of any square or rectangle see above will always intersect at the exact center of the figure in other words at a point equidistant from top and bottom and from left and right edges. Thus on this ping pong table seen directly from above the two diagonals will naturally intersect at the net which is equidistant from the ends. Now when the table is drawn in perspective where should the net be placed If equidistant from the ends the result is wrong below . But if located at the intersection of the diagonals the result remains true. Imagine the diagonals as actual lines ruled on the table. THEREFORE TO LOCATE A MIDPOINT QUICKLY AND ACCURATELY - USE DIAGONALS. Equal Spacing By Diagonals 69 To draw equally-spaced receding elements such as lampposts first sketch two of them between the desired top and bottom guide lines leading to their vanishing point. Now let s develop this further in side view far right . Step A Draw diagonals between 1 and 2 to determine midpoint. A horizontal line through this point gives us midpoint of 1 2 and all similar verticals. Step B Draw diagonals from 1 through midpoint of 2 to locate 3 . Since the diagonals place 2 exactly midway between 1 and 3 the location of 3 must be correct. Step C Subsequent equidistant verticals are located by similar diagonals. Note It isn t necessary to draw both diagonals. One of them used with the center line gives the same result. The application of these steps in perspective will assure equally-spaced elements drawn with proper convergence and foreshortening. BELOW ARE SEVERAL EXAMPLES OF THIS METHOD. STUDY THE VARIOUS APPLICATIONS. 70 Subdividing A Surface By Diagonals Suppose we wanted to divide face A of this object into two equal spaces face B into four equal spaces and the top into eight equal spaces. BELOW is the solution when each .