ECOR 1047 Notes - Sketching and Drawing Techniques PDF

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Sketching and Drawing Techniques Sketching Techniques The contours of an object are the main outlines that separate it from the surrounding space. To think about object contours, think: contrast between positive and negative space. Positive space: the space occupied by the object. Negative space: the unoccupied space around it.

Viewpoints and Shading Need to maintain a consistent viewpoint, like a camera does. Adding shading to your sketch gives a more realistic appearance because it represents the way the actual object would reflect light.

Edges and Vertices Edges: where two planes meet – represented by a line. Where two surfaces intersect. Vertices: a vertex (plural) of a solid is formed where three or more surfaces intersect. Point: used to represent a location in space but has no width, height, or depth – no dimension to it. Line: used in drawings to represent the edge of a solid object.

Angles Make sure you always specify the angles in drawings. Must be consistent between drawings.

Drawings and Sketches Sketch: done very quickly, not neat or accurate, but something quick you can do to convey your idea visually to someone. Drawing: something that has taken more time – neat has is legible, formal – final submission of a project. Keep in mind when drawing: 1. Accuracy – show information correctly. 2. Speed – work smarter to learn techniques to speed up your sketching and CAD drawing while still showing accurate results 3. Legibility – drawing must be clear and legible – give attention to details. 4. Neatness – must be clean and clear and easy to understand.

Freehand Sketch 

Helpful way to organize your thoughts and record ideas.

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Quick, low-cost way to explore various solutions to design problems so the best choice can be made.

Technique of Lines The difference between a drawing and a freehand sketch lies in the character or technique of the lines.  

A good freehand line is not expected to be as rigidly straight or exactly uniform. A good freehand line shows freedom and variety, where as CAD will be exact.

Line Weights   

Thick lines should be twice the width of thin lines Thickness do not have to be exact, but there should be an obvious difference between thick and thin lines Because visible lines and cutting plane lines are the two thick line patterns, other lines should be distinctly thinner in comparison.

Sketching Straight Lines     

Don’t draw from the tip of the pencil Draw from shoulders – move arms Light sweeps before Keep eye where you want to end up. Once happy with line, apply more pressure to darken line

Methods for Sketching Circles

Methods for Sketching Arcs

Maintaining Proportions The most important rule in freehand sketching is to keep the sketch in proportions, which means to accurately represent the size and position of each part in relation to the whole – think as ratio.  

to maintain proportions, determine the relative proportions of height to width and lightly block them in. you can mark a unit on the edge of a strip of paper or use your pencil to gauge how many units and high the object is.

One-View Drawings Frequently, a single view supplemented by notes and dimensions is enough information to describe the shape of a relatively simple object. Only use on objects that are simple, where an extra view is not necessary – only use when you can add the missing dimension easily and quickly (indicating through words on the drawing).

Fractions Do’s and Don’ts    

never let numerals touch the fraction bar. Centre the denominator under the numerator. Avoid using an inclined fraction bar, except when lettering in a narrow space, as in a parts list. Make the fraction bar slightly loner than the widest part of the fraction.

Lettering Spacing of Letters and Words Uniform spacing between letters is done by eye. Contrary to what might seem logical, putting equal distances from letter to letter causes them to appear unequally spaced. Space letter closely within words to make each a compact unit, but space words well enough apart to clearly separate them from adjacent words. In most cases, the title and related information are lettered in title boxes or title strips. When lettering by hand, arrange the title symmetrically about an imaginary centerline.

Drawing Title Block Typical Sheet Sizes and Borders  

Margins and borders zones

Title Block The title block is located in the lower right hand corner of the format. Standard area in the title block provide the information as shown below:

Oblique and Isometric Drawing Pictorial Sketching Perspective view – looks like there is some dimension. The vertical lines will stay parallel, the other lines will not as they will come together to a vanishing point. Not drawn as a box Isometric view – when you can see three sides of the object, but the front view is shown with a vertical line, each of the lines are 30 degrees from the horizontal. Not looking directly at the front, side or top. Vertical and horizontal lines stay parallel. Oblique view – see the entire front of the object, slightly angled view (between 30 – 60 degrees – 45 degrees) allowing for parts of the top and side to be seen. Vertical and horizontal lines stay parallel. A pictorial sketch represents a 3D object on a 2D sheet of paper by orienting the object so you can see its: width, height and depth in a single view.

Isometric Drawing Steps

Oblique Drawing Steps...