tailieunhanh - Perspective Drawing Handbook - Phần 3

Tài liệu tham khảo bằng tiếng Anh về hội họa - Perspective Drawing Handbook - Phần 3 | Chapter 6 DRAWING THE CUBE - PREREQUISITE TO UNDERSTANDING PERSPECTIVE Drawing the simple cube or any rectangular prism such as a brick a book or the . Secretariat from many viewpoints is an important exercise which reveals and explores basic perspective principles. The following pages dramatize many of these. But these studies can only point to the problems involved and help to stimulate your powers of observation. To draw properly you must supplement them with intensive sketching and observation of your own. Get into this habit The six sides of a cube or any rectangular prism are edged by three sets of parallel lines. When the cube rests on a horizontal surface such as a table top one set of lines is vertical . perpendicular to the ground the other two sets are horizontal . level with the ground and at right angles to each other. ON THE FOLLOWING PAGES -VERTICALS WILL BE INDI- CATED BY PIPES -ONE SET OF HORIZONTALS WILL BE INDICATED BY CHAINS -THE OTHER SET OF HORIZONTALS WILL BE INDICATED BY WIRES NOW A QUICK REVIEW We see things as shown on pages 18 and 19 by means of a central visual ray surrounded by a cone of vision. The central visual ray focuses upon the center of interest while the cone of vision defines the roughly circular area within which we can see things clearly. Perpendicular to the central visual ray is the picture plane which may be thought of as a piece of glass or the drawing paper or canvas itself. The observer s face will also be considered perpendicular to the central visual ray hence always parallel to the picture plane. Keep this schema in mind. Also recall the following points Lines and planes parallel to the observer s face and consequently to the picture plane undergo no distortion but maintain their true directions and shapes. Lines and planes which are not parallel to the observer s face picture plane appear to converge and foreshorten. Such lines are sometimes described as receding. The vanishing point for any set of .