Part 1 Basic Drawing Skills
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Transcript of Part 1 Basic Drawing Skills
CIVL1014 – Surveying and Drawing DRAWING LECTURE
Part 1: Basic Drawing Skills
THE UNIVERSITY OF HONG KONGDr. Ray Su
Department of Civil Engineering
(office: HW 6(office: HW 6--6, Tel. no.: 2859 26486, Tel. no.: 2859 2648Email: Email: [email protected]@hkucc.hku.hk))
Tutor: Dr. YP Huang (HW 514B, Tel. 852-2859 7067 , email: [email protected])
Kadoorie
Biological Sciences Building
The framing plan
Kadoorie
Biological Sciences Building
The RC details
The border
Informationpanel
Title block
General Information•
The course does not have a written examination. In-
course assessment is based on drawing assignments.•
The aim of this course is to familiarize the students with the techniques for reading and production
of
drawings. •
An engineer is not expected
to be a drawing
technician but he/she should be able to make
a neat drawing if required. It is important that an engineer should know how to communicate his/her design to the project team with drawings.
•
Engineering drawing is a graphical language which is used by engineers for communication. In order that an engineering drawing can be read and properly interpreted by engineers and other members involved in a project, some common practices, conventions and standards
should be observed.
General Information•
Lecture is devised to teach the students to understand what a drawing is; how it is produced
and
what it is used for.•
Students will be making drawings of their own on framing plans and details of reinforced concrete and steel structures.
•
Drawings prepared on tracing papers will be printed through arrangements by Department. The costs for printing will be borne by students. During the semester, all drawings will be returned to students after marking by tutors.
•
The submission of assignments should adhere strictly to the time schedule. Any late submission will be penalized by deduction of marks.
General InformationTentative schedule of this semester
Assignments 1 & 2 and 3 & 4 are submitted on 4 Nov and 25 Nov respectively
Thursday (3:00-4:55pm) Friday (3:00-3:55pm)
1 Sep 2 Sep
8 Sep 9 Sep
15 Sep 16 Sep
22 Sep 23 Sep
29 Sep Cancelled due to Nesat 30 Sep Engg. Drawing (at MWT1)
6 Oct Engg. Drawing (at MWT1) 7 Oct Engg. Drawing (at HW232)
13 Oct Engg. Drawing (at MWT1) 14 Oct Engg. Drawing (at HW232)
18 Oct Make-up Lecture from 10am to 1pm (Tuesday) at MWT1
21 Oct Reading week
27 Oct Engg. Drawing (at MWT1) 28 Oct Cancelled due to Open Day
3 Nov Engg. Drawing (at MWT1) 4 Nov Engg. Drawing (at HW232)
10 Nov Engg. Drawing (at MWT1) 11 Nov Engg. Drawing (at HW232)
17 Nov 18 Nov
24 Nov 25 Nov
Figure 1. Relationship between the principal members of a project development group
The design team The design team communicates by communicates by means of means of drawings and drawings and letters rather letters rather than design than design calculationscalculations
Why drawings are important for Engineers?
•
Design calculations
vs
Drawings•
In the coming years, engineering drawing is directly useful for surveying part
and the courses ED&C
and
FYP, and indirectly useful for T&D.•
After graduation, sketching skills can help you to (i) develop preliminary engineering schemes, (ii) prepare sketches
to instruct draftsmen to draw the formal
drawings (using AutoCAD), (iii) communicate with Client, Architects, Contractors, Engineers in other
fields, QS, Planners , and (iv) sit for the professional examinations.
Hand drawings vs
CAD drawings
Hand drawings CAD drawings
Sketches –
by engineers Detailed drawings –
by draftsmen
Paper & pencils Computers & plotters
Faster for complicated dwgs Faster for repeated & simple dwgs
Not good for amendments Convenient for amendments
Good for presenting ideas in consultancy meetings, professional examinations
Good for detailed design, formal submission, more accurate, usually higher quality and can link up with computer programs
Not good for filing Easier for filing
Drawing Sheets
•
Tracing paper is to be used and 85g/m2
quality is recommended. The size should be A1 (841mm×594mm).
Designation Size (mm X mm)
A0 841X1189
A1 594X841
A2 420X594
A3 297X420
A4 210X297 Drawing sheet sizes
Drawing Equipments
•
Set squares of 60o
and 45o
•
Compass•
Scale rulers (1:100, 1:200, 1:250, 1:300, 1:400 and 1:500) in metric units
•
Pencils •
Erasers
•
Erasing shield•
ACAD 2009
Set square
Scale ruler
compass
Scale rules
The two types of scale rules
(a) Triangular cross-section
(b) Flat cross-section
Actual distance = 5mThe scale used is 1: 200The scale used is 1: 200Drawing distance = Drawing distance = 5000/200=25mm5000/200=25mm
25mm
Erasing shield
The red line is to be removed.
The border
Informationpanel
Title block
Title Block
Title Block•
Typical title block contains essential information required for the identification and interpretation of drawings. The information usually include
–
Project title e.g. Biological Sciences Building–
Drawing number with provision for revision suffix e.g. S/L/11 (B)
–
Drawing title e.g. 9th
Floor Layout Plan–
Projection symbol e.g. third angle projection symbol–
Scale e.g. 1:100–
Date of drawing e.g. August 1997–
Name of Client e.g. The University of Hong Kong–
Office of origin e.g. Ove
Arup & Partners HK Ltd–
Office project number e.g. 22003–
Identity of persons involved in the design, draughting
and checking
Title Block for this course
PROJECTIONS
Font height = 5mm
Font height = 3mm
Font height Font height = 4mm= 4mm
Font height = 5mm
Title Block
Title Block
Examples of size and position of title and information panels
A1 size
Used in this course
Some common practices
Title Block•
A standard title block is to be placed at the bottom right hand corner of the drawing.
•
The minimum border width is 20mm except that 25mm minimum is required for the left hand border.
25mm minimum25mm minimum
1mm 1mm
20mm minimum20mm minimum
Scale•
Drawings should be drawn with an appropriate scale so that all necessary information related to each drawing can be easily presented. Recommended scales for civil and structural engineering drawings are 1:10, 1:25 (1:20), 1:50, 1:100 and 1:200–
(dimensions on drawing : actual dimensions on site)
Linework
•
Different line thicknesses and line types•
For good presentation, all lines should be black and firm. Each line should be of consistent good presentation and easy reading.
Do not mix pencil and ink line on one drawing. Recommended thickness of lines and their typical applications are shown in the sketch attached.
Linework
Thickness of line and line types
(cut section)
and outlines of structural members
Various line thickness
Various line types
Linework
Thickness of line and line types
or Adjacent Structures (for information)
1mm min. for gaps 2-4mm long for line segment
1mm min. for gaps2-3mm for shorter line segment5-15mm for longer line segment
Various line types
Linework
Typical application
Linework
Typical application
Lettering
•
Avoid ambiguity, reading difficulty
and wrong interpretation
by others
•
If you can write neat lettering, it is easier for your future supervisors or clients to have confidence in
your work and in you.
•
Lettering
looks simple but it requires a lot of time and patience
to practice and to do
it well.
Why do we need good lettering in engineering drawings?
Lettering•
All writing should be black
and of consistent density.
They should be easily read and unambiguous.•
Either vertical or sloping characters can be used but they must not be mixed on any one drawing.
•
The height of capital characters should be about 7mm for titles and 2.5mm for notes and dimensions. For lower case letters, the height should be about 0.6 of the corresponding capitals.
Lettering
Application Drawing sheet size
Minimum character height
Upper case and numerals (mm)
Lower case (mm)
Titles, drawing numerals, etc.
A0, A1, A2 and A3 7 4
A4 5 3
Dimensions and notes
A0 3.5 2
A1, A2, A3 and A4 2.5 1.5
Common Heights of letters and numeralsExtracted from: Standard Method of Detailing Structural Concrete, The Institution of Structural Engineers and The Concrete Society (1989)
Lettering
Example of letters
Lettering
Guide lines for Lower case Letters
The guide lines are drawn softly and they do not need to be erased.
Presenting 3-D Civil/ Building Structures in 2-D Spaces
••
Option 1: Isometric ViewOption 1: Isometric View••
Option 2: ProjectionOption 2: Projection
x y
z
Isometric View
120o between coordinates axes
AABB
CC
DD
EE GG
FF
Only visible lines are shown
Draw a cube with lengths of 4 units
Note: Dimensions parallel
to the coordinate axes can be measured directly from figure
1 unit in x dir.
12
34
43
21
1
2
3
4
dimensions not measurable from the figure
x y
z
Isometric View
If the corners of unit length are removed from the cube:
Isometric View
x y
zWe can use this method to draw any 3D objects.
However, what are the drawbacks of using isometric view in engineering drawing?
Hidden parts have not been shown. It is difficult to show the dimensions and time consuming to draw a 3D object.
Isometric view Orthographic projections
Projection (First angle)
Front View(view projected onto y-z plane)
View of Left Side
Plan View
Side view put on the Side view put on the opposite sideopposite side
View of left Side
x y
z
y-z plane: plane of projection
Orthographic projections
Projection (Third angle)Isometric view
x y
z
Front View
View of Right Side
Plan View
Side view put on the Side view put on the viewing sideviewing side
View of Left Side
Projection
In general, any three orthogonal views (projections) are sufficient to present all information of an object.
Engineering drawings should be prepared using Third Angle Projection. This projection is illustrated in Fig.4
(i)
the elevation or side view of the member.(ii)
The plan or top view above the elevation.(iii)The views at each end looking directly on the end and
adjacent to it.(iv)
The bottom or plan view on the bottom side is drawn as a
view looking up from the under side.
Fig 4. – Example of third angle projection.
Projection
(i)
(ii)
(iii) (iii)
(iv)
Transferring dimensions between top and side views
•Using dividers
•Using scales
•Using 45o
miter (inclined) line
Projection
Top view
Side view
Front view
8
2 4 3
Transferring Isometric View into Third Angle Projections:
•
Three views required
•
Measure dimensions of lines parallel to coordinate axes
Projection
xy
z
Measure the coordinates of corner points
(x1 ,y1 ,z1 )
Dimensions of red
lines parallel to coordinate axes
can be measured directly from the figure
Poor
Projection
Outside corners intersect Poor
Good
Hidden lines intersect without a gap
PoorInside corners intersect but do not cross
Poor
PLAN
VIEW OF RIGHT SIDE
Projection
FRONT VIEW
Viewing direction
Try to Sketch the 3D View
SECTION A-A
SECTION B-B
Projection
DimensioningExtension Lines:
• Thin continuous lines
• Preferably starting just near outline of object
• Extending a little beyond dimension line
100
70Dimension Lines:
• Thin continuous lines
• Placed outside the view if practicable
• may be interrupted to insert dimensions
CLCentre lines (Symbol
)
• Thin
chain dotted lines
• To represent axes of symmetrical parts and to denote centers
CL
Fig. 5 Dimension lines and extension lines
Dimensioning
456
123
234
234
35
Dia 250
222DonDon’’t t over over dimensiondimension
Note: All units are in millimetres
unless otherwise specified
123
456
Placement of dimension lines and extension lines:
Fig 6. Placing of dimension lines
Dimensioning
Shorter insideAvoid overlapping of D line
Extension line extended to edge
D line outsidedrawing object
Fig 7. Use of arrow heads and dots
Fig 8. Inclined dimension lines
Dimensioning
General rule: number to be placed above dimension lines.
End of dimension line defined by arrow head
Limited space: (1) arrow head outside dimension line(2) use dot or circle instead of arrow head
Dimension to be given where shapes are shown:
Fig 9.
Dimensioning
Each dimension is given in the contour view
Every dimension is given in the wrong view
Simple rules for civil/structural drawings:Plan –
horizontal dimensions (x and y coordinates)Elevation/Section –
vertical dimensions (z coordinate)
doesn’t look like a circle
Recess
Dimensions to be lined up and grouped together as much as possible:
Fig 10.
Dimensioning
An application of dimensioning:
Fig 11.
Dimensioning
Elevation view
Plan view
View from Right side
3D viewDimensions shown
at contour views
Shorter dimensions put inside
No over dimensioning
The termination of dimension lines can be indicated by:
(a)
open arrowheads;
(b) solid arrowheads;
(d) Dots or circles on the dimension line.
(c) short oblique strokes cutting the dimensions line;
Termination of Dimension Lines
Dimensions should normally be to the nearest millimetre.
w3w
Length equal the width of arrowhead
Assignment 1•
6 problems on third angle projection•
1 from each problem sheet•
last digit of problem no. = last digit of university no.•
dimensioning required (to be rounded up to nearest mm)•
dimensions to be measured from figures•
font height for dimensions = 2.5mm•
font height for titles = 5mm•
use suitable drawing scale (2:1
or 3:1)•
A1-size hand drawings to be submitted.
Problem Sheets 1 –
4
Isometric View Problems
Problem sheet 1
A
A
B
B
C
C
Example
For locating the vertex
x
y
zSet up coordinate axes
Measure the dimensions to the nearest mm (or up to 0.5mm) For the lines parallel to
the coordinate axes
x1
y1
z1(x1 ,y1 ,z1 )After finding out
the coordinates for all the nodes, draw the three different views in third angle projection.
Show the measured dimensions
(up to millimeters) on the scaled drawing
Problem Sheets 5 –
6
Missing View Problems
3rd ANGLE PROJECTIONS
Problem sheet 5
Missing view(may have more than one solution) ?
Example
DUE DATE: DUE DATE: 44
November 2011November 2011(during the lecture)(during the lecture)
Use upper cases in the drawingUse upper cases in the drawingWrite down PLAN, FRONT VIEW or VIEW OF RIGHT SIDE below the view
Show the measured dimensions on the drawing
The End
References•
Standard Method of Detailing Structural Concrete, The Institution of Structural Engineers and The Concrete Society (1989)
•
A Hayward and F Weare, Steel Detailer’s Manual, Blackwell Scientific Publications, Oxford (1992)
•
BS 308 Engineering Drawing Practice, Parts 1-3 (1993)•
BS 1192 Construction Drawing Practice, Parts 1-5 (1987)•
James H. Earle, Drafting Technology, 2nd
Edition, Addison-
Wisley, Wokingham England, 1986
•
Frederick E. Giesecke
et al. Principles of Engineering Graphics, 2nd
Edition, Maxwell Macmillan, New York, 1994.
References•
R N Roth and L A Van Haeringen, Australian engineering drawing handbook, Parts 1-2, Barton, A.C.T. : Institution of Engineers (1998)
•
Highways Department Standard Drawings, HKSAR (1998)•
CAD Standard for Works Projects, Environment, Transport & Works Bureau, HKSAR (2002)
•
PNAP 58 Submissions to the Buildings Department•
PNAP 127 Colouring
of Plans –
Building (Administration) Regulation 14(3)
•
PNAP 135 Imaging Standards for Plans