Sketching Techniques

Technical Drawing Program

SKETCHING TECHNIQUES

Sketching is a freehand drawing process that allows detailers, designers, engineers, architects, technicians and trades persons to record their ideas quickly on paper without the use of tools. Once they have recorded their ideas, they can revise and refine their sketches for presentation to their supervisors or clients. Sketching is also helpful in preliminary planning of a drawing or layout before using tools.
Sketches can be made on any type of paper: white bond (preferred), newsprint, napkins or transparent tracing paper. White papers with light blue or gray grid lines at different grid spacings of1/4", 1/8" or 1/10" are helpful to beginners for sketching objects in the proper proportions. Angled grids for isometric, oblique and perspective views are available for three-dimensional work.
A medium weight (H or HB) lead or drawing pencil with a rounded point works best for making freehand sketches. This pencil is hard enough to make a light line with a little finger pressure and soft enough to make a line darker by using more pressure.
Horizontal lines should be sketched by moving the hand and pencil from the left to the right if right handed. Avoid rotating your wrist as this will cause the line to arc. 5. Vertical lines should be sketched by moving the hand and pencil from the top in a downward direction. Keep the wrist locked to avoid arcing of line.
Angled lines should be sketched by moving the hand and pencil from the left to the right and angling upward or downward. Rotating the paper so lines are horizontal or vertical is also a good practice. Avoid rotating your wrist as this will cause the line to arc.
Arcs and circles should be sketched by creating horizontal and vertical center lines at the center point of the arc or circle. Next estimate the radius of the arc or circle on each center line and form a box with lines parallel to the center lines. Now start at the top of the box and create four arcs moving the pencil left to right and rotating the paper each time.
A multiview two dimensional (2D) sketch shows the actual shape of an object from different directions that are 90° apart. A typical multiview sketch will include views from the top, front and right side. The back, bottom and left side views are optional depending on the complexity of the objects shape. See Multiview Sketching Steps.
A pictorial three dimensional (3D) sketch shows the overall shape of an object from one direction. There are three types of pictorial sketches: isometric, oblique and perspective. The isometric is the easiest to create as actual measurements are used and the shape of arcs and circles is consistent on all surfaces. The cabinet oblique sketch is best used for furniture or cylindrical shaped objects as a normal front view is used. Perspective sketches provide the most realistic view of an object but are more difficult to create as all distances must be shortened. See Pictorial Sketching Steps.
Architects use two types of sketches, floor plans and elevations, to show the shape of a house or building. A floor plan sketch is similar to a top view with the roof removed and shows interior walls, windows, doors, appliances, fixtures, built-in cabinetry and stairways. An elevation is similar to a front view and shows the height of the structure plus exterior materials like siding, doors, windows, trim and roofing.

Four styles of lines are used to create the views of an object. Visible or object lines are thick, solid lines and are used to show the outline or the visible edges of the object. Hidden lines are medium thick, dashed lines and are used to show edges or surfaces on the inside of an object or behind the top, front or side surfaces. Center lines are thin lines composed of long and short dashes and are used to locate the center point of holes or the central axis of a cylinder. Construction lines are very thin, light lines and are used to layout preliminary shapes. Construction lines should not have to be erased. See Alphabet of Lines.

The ability to create fast, understandable views of objects with only a pencil and a piece of paper is extremely important to being successful as an engineer, designer, architect, builder, manufacturer or craftsman. All objects are composed of lines: horizontal lines, vertical lines, angular lines, circular lines, arcs and ellipses. The procedures shown below describe the movement of your hand for the sketching of lines, circles and ellipses. Very light construction lines should be used when doing arcs, circles and ellipses. Practicing these techniques will help you develop skill in the creation of lines, arcs, circles, ellipses, and views of objects.

Revised: 10/5/06