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Publisher

The Goodheart-Willcox Co., Inc.

Tinley Park, Illinois

© Goodheart-Willcox Co., Inc.

1

Permission granted to reproduce for educational use only

Chapter 4

Drawing

Instruments and

Techniques


2


Chapter 4 Overview

• Introduction

• Orthographic Projection

• Three Principal Views

• Architectural Manual Drafting Equipment

• Freehand Sketching

3 (continued)



Chapter 4 Overview

• Computer-Aided Drafting and Design

• Lines Used in Architectural Drafting

• Architectural Lettering

• CADD Symbols Library

4



Learning Objectives

• Define the three principal views in orthographic projection.

• List and explain the use of architectural drafting equipment.

• Explain the difference between size and scale.

• Reproduce the standard alphabet of lines.

(continued)

5



Learning Objectives

• Demonstrate an acceptable architectural lettering style.

• Freehand sketch.

• Identify the basic components of a

CADD workstation.

6



Introduction

• Understanding basic drafting practices and the use of equipment is expected before attempting architectural drafting.

• Most of the equipment and principles are similar to mechanical drafting.

• A review of the basic drawing concepts will establish a foundation for architectural drafting.

7



Orthographic Projection

• Orthographic projection is the most basic drafting technique.

– A means of representing the height, width, and depth of a three-dimensional object on two-dimensional paper.

– The object is viewed at infinity, thus projection lines are parallel to each other.

– Typically, three views are used.

8



Orthographic Projection

• This camp cottage shows the arrangement of views in orthographic projection.

9



Three Principal Views

• The three principal views in orthographic projection are the top, front, and right side views.

• In architectural drafting, the views are similar but have different names.

– The top view of a house is called a plan view ; used as the basis for most other drawings.

(continued)

10





– The floor plan is a top view in section taken about half way up the wall.

– The front elevation in architectural drafting is the same as the front view in mechanical drafting.

– Architectural drafters ordinarily draw a view of each side of the structure, which are called elevations.

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• How orthographic views are projected.

12



Drafting Equipment

• An architectural drafter uses equipment that is designed for specific purposes.

• Using this specialized equipment requires skill and understanding.

– The manual drafter uses traditional equipment such as triangles and scales.

– The CADD drafter produces drawings on a computer.

(continued)

13



Drafting Equipment

• Common manual drafting equipment.

(Koh-I-Noor Rapidograph, Inc.)


14

(continued)


Drafting Equipment

• Common CADD workstation.

15



Traditional Drafting Equipment

• Pencils used in manual drafting are available in wood and mechanical types.

(continued)

16

(Berol USA)




• The most popular types of erasers used by architectural drafters are rubber and plastic.

(continued)

17




• Electric erasers can be used to quickly erase large areas.

(continued)

18

(Staedtler Mars GmbH & Co.)




• Erasing shields are made of metal or plastic.

They are thin to provide for accurate erasing.

(continued)

19





• Most architectural drawings are finished on tracing paper, velum, or drafting film.

• Paper Sizes

– A-size (9" x 12")

– B-size (12" x 18")

– C-size (18" x 24")

– D-size (24" x 36")

– E-size (36" x 48")

(continued)

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• Common paper sizes.

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(continued)



• Drawing Boards

– Standard sizes:12" x 18", 18" x 24", 24" x

36", and 30" x 42".

– Materials: White pine, basswood, and plywood.

• T-Squares

– Materials: Wood, metal, plastics, and a combination.

(continued)



22


• Drafting machines speed the work of the manual drafter and are usually permanently attached to the drafting table.

(continued)

23

(Vemco Corporation)




• Triangles are used to draw nonhorizontal lines.

– 45° and 30°-60° triangles.

– Metal or plastic.

– Adjustable triangle

(shown).



24

(continued)



• Protractors are used for measuring angles.

– Semicircular and circular styles.

(continued)



25


• Architectural drafters use architect’s, engineer’s, and combination scales.

26



Architect’s Scale

• Divided into 3/32", 3/16", 1/8", 1/4", 1/2",

3/8", 3/4", 1", 1-1/2", and 3" to the foot.

• One edge divided into 16 parts to the inch.

• Divisions based on 12 units to the foot.

• Used for most work.

27



Engineer’s Scale

• Divided into 10, 20, 30, 40, 50, and 60 parts to the inch.

• Divisions based on 10 units to the inch.

• The engineer’s scale is used by the architectural drafter to draw plot plans.

28



Combination Scale

• Divided into 1/8", 1/4", 1/2", 3/8", 3/4", and 1" to the foot.

• One edge is divided into 50 parts to the inch.

• One edge is divided into 16 parts to the inch.

• Divisions include 12 units to the foot and 10 units to the inch.

29



Size Compared to Scale

• “Size” and “scale” need clarification.

• “Half size” means the drawing is one half as large as the object.

• Scale: 1/2" = 1'-0" means the drawing is 1/2 scale.

• 1/2 scale means 1/2" on the drawing =

1'-0" on the object.

• Residential plans are generally 1/4" =

1'-0" scale.

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Reading the Scale

• The 1/8" = 1'-0" and 1/4"=1'-0" scales are printed on the upper edge of this architect’s scale.

(continued)

31



Reading the Scale

• The proper method of measuring 16'-4" using the 1/4" = 1'-0" scale.

32




• Dividers are used to divide a line into a number of parts.

– Three types are shown.

(continued)



33


• The compass is used to draw circles, arcs, or radii.

– Center-wheel type shown.

(continued)

34




• The beam compass is used to draw large arcs.

(continued)

35




• Lettering guides are used to draw guidelines for hand lettering.

– Types: Ames and

Braddock-Rowe.

(continued)



36


• Irregular curves are used to draw curved lines that cannot be drawn with a compass.

– Flexible curve.

(continued)



37


• The case instruments may include dividers, compass, lining pens, pencil pointers, spare parts, small screwdriver, and various other instruments.

38

(continued)




• Lettering devices are used when uniformity of letters is essential.

– Stencil type.

(continued)



39


• Technical pens are used to ink a drawing. Points are interchangeable and range from 000 to 8.

(continued)

40





• Templates serve as guides in drawing special lines or symbols. Most are made of plastic.

(Berol USA)


41

(continued)



• Grids are available in a wide variety of sizes and forms: square, isometric, and perspective.

42



Freehand Sketching

• Freehand sketching is a method of making a drawing without the use of instruments.

– Most designers use sketches to “think through” an idea before making the final drawing.

– Freehand sketching requires only a pencil and plain or grid paper.

(continued)

43



Freehand Sketching

• Cross-section paper may be used for freehand sketching.

44



Sketching Technique

• When sketching, hold the pencil with a grip firm enough to control the strokes.

• Your arm and hand should have a free and easy movement.

• As you sketch, rotate the pencil slightly between the strokes to retain the point longer.

• Initial lines should be sharp and light.

(continued)



45

Sketching Technique

• Apply light pressure to avoid making grooves in the paper.

• Keep your eye on the point where the line will end; use a series of short strokes to reach that point.

• When all the lines are sketched, go back and darken the lines.

• Strive for neatness and good technique.

(continued)



46

Sketching Technique

• When sketching, grip your the pencil farther back than you normally would.

47



Sketching Horizontal Lines

• There are four basic steps.

48



Sketching Vertical Lines

• There are four basic steps.


49


Sketching Inclined Lines

• Locate the end points of the line.

• Position arm for trial movement.

• Sketch several short, light lines.

• Focus on end point.

• Darken the line.

50



Sketching an Angle

• First, sketch a right angle (90 °).

• Subdivide the right angle to get the angle you desire.

51



Sketching Circles and Arcs

• There are several methods of sketching circles and arcs:

– Centerline method.

– Enclosing square method.

– Hand-pivot method.

– Free-circle method.

• All are sufficiently accurate, so use the best method for a particular situation.

52



Centerline Method

• Locate centerlines.

• Mark off radius.

• Position arm.

• Sketch the circle in short sweeps.

• Darken the circle.

53



Enclosing Square Method

• Locate centerlines.

• Sketch a box equal to the diameter.

• Sketch arcs where the centerlines cross the box line.

• Sketch the circle.

54



Hand-Pivot Method

• First, position the pencil and small finger. Then, rotate the paper to sketch the circle.

55



Sketching Ellipses

• The rectangular method for sketching ellipses is similar to the enclosing square method for circles.

56



Sketching Irregular Curves

• Sketch an irregular curve by connecting a series of points at intervals of 1/4" to

1/2" along its path.

57



Proportion in Sketching

• Proportion is the size relationship of one part to another or to the whole object.

• Keep the same width, height, and depth in proportion.

– Unit method.

– Pencil-sight method.

(continued)



58

Proportion in Sketching

• Gauge proportions using the pencilsight method.

59



CADD

• Computer-aided drafting and design

(CADD) consists of hardware and software components.

– Hardware components include the physical devices.

– Software programs are used to create drawings or other documents.

• Output devices produce drawing hard copies.

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CADD Hardware


61


CADD Software

• The programming commands tell the computer hardware which drawing and design tasks to perform.

• General and AEC CADD are available.

(continued)



62

CADD Software

• This is a CADD-generated drawing.

63

(SoftPlan Systems, Inc.)



CADD Output Devices

• Plotter

– Produces high-quality drawings (as shown) using pens or pencils.

• Printer

– Laser and inkjet printers also produce good quality.

64

(DesignJet Division, Hewlett-Packard)



Architectural Alphabet of Lines

• Border Lines

• Object Lines

• Hidden Lines

• Centerlines

• Extension Lines

• Dimension Lines

• Long Break Lines

• Short Break Lines

• Cutting-Plane Lines

• Section Lines

• Guidelines

• Construction Lines

65



Border Lines

• Border lines are very heavy lines used to form a boundary for the drawing.

• Use a 0.70mm pen.

66



Object Lines

• Object lines are heavy lines that outline features of an object.


67



Hidden Lines

• Hidden lines represent edges that are behind a visible surface in a given view.


68



Centerlines

• Centerlines indicate the center of holes and symmetrical objects, such as windows and doors.


69



Extension Lines

Extension lines

• Extension lines are used to denote the termination points of a dimension line.


70



Dimension Lines

• Dimension lines are used to show size and location. They have a dimension figure halfway between the ends of the dimension line.


71



Long Break Lines

• Long break lines are used to show that not all of the part is shown.


72



Short Break Lines

• Short break lines show part of the object broken away.


73



Cutting-Plane Lines

• Cutting-plane lines are used to show where the object is sectioned.


74



Section (Crosshatch) Lines

• Section lines or crosshatch lines are used to show that a feature is sectioned.

• May represent different types of material.


75



Guidelines

• Guidelines are used in hand lettering to keep lettering straight.

• Very light lines.

• Drawn in pencil only.

76



Construction Lines

• Construction lines are used in the process of constructing a drawing.

• Should not be reproduced.

• Not inked or plotted.

77



Line Type Application

• In manual drafting, all lines are black and vary only in width. Colors may be used in CADD.

78



Pencil Hardness Guidelines

• Range from 9H (very hard) to 9B (very soft).

• Use 6H for construction and guidelines.

• Use 4H for dimension, extension, center, leader, long break, and section lines .

• Use 2H for object, hidden, cutting plane, short break, and border lines.

• Use H for lettering.

79



Architectural Lettering

• There is no single style of architectural lettering. Most lean toward the artistic.

• Develop your own style.

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Developing a Lettering Style

• Use guidelines for hand lettering.

• Experiment with variations of letters.

• Select an artistic lettering style.

• Apply a basic technique to similar letters.

• Make a mental picture of each letter.

• Practice “your” style to gain precision.

• Use your style in your work.

(continued)

81




• Variations of letters add interest.

(continued)

82




• The space between letters in a word is not constant.

• Learn the spacing that looks best.

(continued)

83




• Words should not appear to run together or be too far apart.

• Space between words should usually equal the height of an uppercase letter.

• Most information lettered on a drawing is 1/8" or 3/32" high.

• Try making the first letter in each word

1/8" and the remainder 3/32" high.

(continued)



84


• Draw the first letter of each word larger than the succeeding letters for emphasis.

85



CADD Symbols Library

• Using a CADD symbols library provides a time savings.

– Standard symbols are included in most

CADD software programs.

– Symbols are stored on the disk and are called up when needed.

– User created symbols are possible.

– Symbols may also be inserted using a digitizing tablet.

86



CADD Symbols Library

• Symbols may be called up from the symbols library.

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