Fundamental principles of technical sketching and visualization techniques Unit B, Objective 4.01

Sketching Tips Rotate paper to facilitate natural ease of drawing. Vertical lines are drawn from top to bottom. Long lines are generated by the using short lines that do not overlap.

Four Basic Drawings Sketches Illustrations Multiview drawings Pictorial drawings

Multiview Drawings A working drawing is a two-dimensional drawing of a three-dimensional object. Consist of six views: top, bottom, front, back, right-hand side, and left-hand side. Most common views drawn are top, front and side. Created using a technique called orthographic projection.

Pictorial Drawings Viewed in such way that several faces appear in a single view. The three most common pictorial drawings are : isometric, oblique and perspective.

Isometric drawings based on three lines or axes, which are equally spaced at 120 degrees apart. In isometric sketches or drawings circles appear as ellipses and can be drawn using the rectangular method or ellipse templates.

Oblique drawings The object is drawn as if you are looking directly at it. The lines making up the other surfaces is drawn at an angle of 30 or 45 degrees.

Two types of Oblique A cavalier oblique ’ s depth is drawn at the original length. A cabinet oblique ’ s depth is drawn at the half the original length.

Perspective drawings are the most realistic of all the pictorial drawings. The object appears three dimensional by using four factors.

Perspective Factors Position of the viewer Drawing is constructed using a projection plane, horizon line, ground line and vanishing points

Types of Perspectives One-point are the most common. Two-point are used by architects and product illustrators. Three-point are limited to the field of commercial art.

Shading for Technical Illustrations Shows the object in shadow and light as it would normally appear in it ’ s natural setting. Surfaces that face the light source will have no shading, while the surfaces away from the source are shaded.