Constructive drawing a picture of outer contours of objects, both visible and invisible, made using construction lines. You create a "skeleton" of the object that you want to draw. And in order to create such a framework, you need to analyze the depicted subject. Constructive design begins with analysis. Look closely, think of what constitutes an object? From which the solids? And what is the locus of the body? This is a cube, sphere, cylinder, cone, prism. If you learn to see things around you, the geometric body, then you can easily create a framework, or, rather, a constructive pattern.
For example, take an ordinary bottle. She accommodates a cylinder, may be a cone (truncated), and, perhaps, a truncated sphere. Or, for example, cabinet, or table – consists of a four-sided prism, or may be of the cubes. Therefore, the first step – learn to find in all that we surrounds the geometric body. This will help to develop three-dimensional thinking. The second step – the image "frame". Need to learn how to place geometric body comprising the depicted object in space.
For This requires knowledge of linear perspective. That is, you need to know what the horizon line, vanishing point, and how to use this knowledge. For example, when we draw an ordinary cube, we represent a line parallel to the faces of the cube so that they converge at a single point on the horizon line. The second point – a center line. It helps create the right design.