Drawing skills and techniques
This paragraph is concerned with the production of drawings. Specifications
and working drawings convey to the contractor/builder the necessary information
to erect and complete a structure. Drawings will vary from company to
company but the following approach is used for this subject:
- Identify and analyse the assignment instruction to ensure you have
a complete view of the scope of work.
- If you have any question clarify the issues with your lecturer.
- Think of possible solutions to all aspects of your assignment and
make, if necessary, freehand multi-view and/or pictorial sketches for
- You should then discuss your ideas with your lecturer.
- If you have a clear understanding of the scope of work you may then
prepare your draft sketches as outlined below.
In Builders Working Drawing you learn how to create orthographic drawing
as well as pictorial drawings.
First and third angle projection
This is a graphical method used in engineering drawings.
The word orthographic is derived from the Greek words orthos-straight,
rectangular and graphos-written, drawn. A drawing of
a structure or part thereof can be drawn using the following projection
(b) oblique and/or (c)
There are two methods of orthographic projections use:
1) first angle projection and 2) third angle
They are based on right angle planes with defined separate spaces ,
or quadrants. Each quadrant could obtain an object to be presented. However,
only two are commonly used, the first and the third as shown in Figure
of projection are approved internationally and the system used is clearly
indicated on all engineering drawings with the following illustrations:
Figure 1 Figure
In which projection architectural and builders working drawings
are represented is generally insignificant. Nearly all of those drawings
do not indicate in which projection they are drawn and it really does
not matter. However, it is important that you understand the basic principles
of orthographic projection and be able to construct orthographic views
Figure 3 |
way to explain the development of a orthographic drawing is to place an
object in a glass cube as shown in the opposite figure. The object surfaces
are then projected on the faces of the cube. The cube like any card box
can be unfolded so that all six surface areas are shown as blow.
Figure 5 shows the unfolded box with the same object as shown in Figure 3.
How to draw objects or components
Adopt the method below for drawing building objects or components.
Choose which view or direction or face will be used as the font view
of the object or component.
The object or component you chose for the front view should have the
longest straight edge..
From the bottom edge of the front view draw feint construction lines
@ 45° as shown in Step 1
Carry on finishing the top view. Start a line below the front view with
sufficient distance for dimensioning of the object or component.
Complete the top view
Use faint construction lines and draw the outline of the side views as
shown in Step 2
Complete the side view with the aid of construction lines as shown in
Always use this method for drawing objects or components.
However, for a Set of Working Drawings use the method outlined
In Drawing 1 you will draw a number of different objects. The views should
always be aligned with each other allowing sufficient space between the
views for dimensions (see Step 1 - Figure 6). Lines that cannot be seen
in a specific view are hidden and shown as dashed lines.
Working drawings for buildings
Orthographic building/construction drawings are a two dimensional
representation of a structure. They are drawn in various scales depending
on the detail and content required and offer the following advantages
compared with other systems:
- It's usually the simplest and quickest method of giving an accurate
representation of an object.
- Only those views that are essential need to be drawn.
- Dimensioning is relatively easy.
- Sectional and part views are easier to construct.
The only disadvantage of this method is that some training is necessary
before you can draw or read a drawing. Sometimes it's easier to draw the
object in perspective view (pictorial view), especially for clients who
have difficulties interpreting orthographic drawings.
Building construction drawings usually show the following views:
For a building application to council the following plans are required:
- Plan view (Floorplan)
- Elevations (faces of the building)
Site plan, b) floor plan(s), c)elevations, d)
All your drawings must be fully dimensioned to enable builders to construct
and build the drawn object.
To draw a complete set of plan for a building do the following:
- First draw a plan-view in pencil on any paper (Plan
- Then draw the section (Plan
2) on another piece of paper. Use Plan
1 to extend the lines and add all vertical elements that
cannot be shown in a plan-view to finish the Section.
- Use Floor plan (Plan
1) and the rearranged Section (Plan
2) to draw the Elevation (Plan
3) as shown below.
- Keep section (Plan
2) and rotate Plan1 90° (clockwise or anticlockwise) and draw another elevation.
- Rotate Plan1 again 90° to complete the next elevation.
- Use the same procedure to complete all elevations.
- Having finished drawing all required items you can now arrange
all items and place them on your board to fit the designated paper
size. Then overlay the transparency paper and trace all views.
All drawings, whether section, details, pictorial views etc. that need
to be produced in ink on transparency paper draw first the item on any
paper and then trace it onto the transparency paper. This allows you to
place the items most appropriately on your designated sheet avoiding running
out of space or overcrowding.
An object can be shown in three pictorial views.
- Isometric projection is a method of portraying, on a single
view, a three-dimensional picture. It can be use for making rough sketches
on site to clarify an issue. The angle between the principal axes is
120°. The scale ratio for isometric drawings is the same for each
principal axis (Y:Z:X = 1:1:1) as can be seen in Figure 2 (a).
- Oblique projection. - In this system, the main view is drawn
as an orthographic projection and the side views are represented on
inclined planes. The angle between the orthogonal and inclined plane
is 45°. The scale ratio for oblique drawings is the same for two
principal axis and half for the inclined plane (Y:Z:X = 1:1:0.5) as
can be seen in Figure 2 (b).
An alternative of the oblique projection is to change the principal
axis, refer to Figure 2 (c). This method gives an more appropriate view
of the object to be drawn.
Great care should be taken when you select a viewing direction in oblique
view. The best viewing direction is when the important details are shown
in the face with the principal axis Y:Z:X = 1:1:0.67. Use the view that shows all details clearly.
(c) oblique alternative
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- Perspective Drawings
A perspective drawing is similar to a photograph: as the lines of an
object recede toward the back,
they appear to converge or become closer together. The advantage of
a perspective drawing over scale and full-size drawings is that the
object looks more like what our eyes perceive if we viewed the actual
object. That is, a three-dimensional perspective is provided. These
drawings are very difficult to construct and not part of this course.
However, nowadays the Computer Aided Drafting packages (CAD) have
3-D facilities build in and the skill to draw in perspective mode
is of no great importance in building and engineering drawing anymore.
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Type of lines
If all lines on a drawing are of the same thickness the drawing may not
be clear or difficult to interpret. However, if the salient features are
shown in thick lines and others in thin lines the drawing is easier to
read and interpret. To ensure uniformity of line types the Australian
and international standards should be used [see ARCHITECTURAL DRAWING
Standards & Conventions (K J Holtom)].
The most common sizes for pens are 0.7, 0.5, 0.35 and 0.25 mm. The minimum
requirements is to have two disposable pens, sizes 0.4 and 0.2 mm. (Disposable
Rotring pens are not recommended because of slow drying.)
If you need to draw a thicker line, the backline technique can
be used. This line is produced by drawing two (2) lines at approximately
line distance apart (with a 0.4 mm pen a 0.7 mm line thickness can be
Pencil lines should be sharp, dense and uniform on drawings that
are not produced in ink. Make sure their is a visible contrast between
the thickness of thick, medium and thin lines. This can be achieved by
using a softer grade for thick lines than that used for the other line
thickness. As a guide use for construction and dimension lines a 2H-lead,
for all other thin lines a H-lead and for thick lines B- or HB- lead.
Smudging of pencil drawings can be avoided if you cover the finish portion
of the drawing with a piece of paper.
Most students may not have to produce complete working drawings in their
working environment. However, it will be beneficial if you develop good
freehand sketching skills. The ability to create detailed views with a
pencil on a piece of paper is extremely important for supervisors or builders.
All details are composed of lines: horizontal, vertical, angular, circular
or elliptical. The procedure below describes the movement of your hand
for sketching lines. A bit of practice is needed to develop the skill
to produce freehand sketches.
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To "letter" a drawing or sketch in a neat and consistent style is very
important. Bad lettering will spoil your drawing. Use single stroke vertical
or sloping letters on your drawing.
For all letters we use only upper case. Normal lettering is made 3 mm
high with 2 mm line spacing and titles 5 mm high with 3 mm line spacing.
Good lettering depends on the following:
- Uniformity of shape (refer to ARCHITECTURAL DRAWING
Standards & Conventions (K J Holtom)
- Uniformity of style (no mixed style on the same drawing)
- Uniformity of size (letter touching upper & lower guide
- Uniformity of line thickness (all strokes & curves
must have the same line thickness)
- Uniformity of slope (use vertical or sloping guide
lines to keep characters upright or sloping)
- Uniformity of spacing (keep white areas between letters
equal and the space between words the same)
To produce good lettering the position of your hand is important. Use
the following guidelines as a basis:
- Your forearm should rest on the drawing board
- Your index finger should be kept as straight as possible along the
pencil. This will help to avoid tension in the hand.
- Your forearm should be at an angle of 75-80° with the line of lettering.
- All strokes should where possible be made from top to bottom and from
right to left.
The most important aspect of pencil lettering is making a uniform dense
black line by applying adequate pressure on the pencil. This depends on
selecting a pencil that has the proper hardness. The selection of the
grade (B, HB or H) depends on the surface of your drawing paper. Try the
different leads for best result!
In ink lettering the thickness depends on the pen used and not on the
pressure applied. If you use tubular pens you should hold them perpendicular
to the paper to avoid varying line thickness.