2 sketching
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MCE216L EngineeringMCE216L Engineering
Drawing and WorkshopDrawing and WorkshopLecture #2Lecture #2
Eng. Rami AliEng. Rami AliFall 2015Fall 2015
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1.1. SKETC!"SKETC!"
2. $%&'ECT!&"S 2. $%&'ECT!&"S (. &%T&%)$!C(. &%T&%)$!C
$%&'ECT!&"$%&'ECT!&"
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*reehand Sketching*reehand SketchingFreehand sketches are a he+p,u+ wa- to organie -our
thoughts and record ideas. The- pro/ide a 0uick +owcostwa- to e3p+ore /arious so+utions to design pro4+e5s sothat the 4est choices can4e 5ade.
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The following are important skills to keep in mind forsketches
And drawings:
1.Accuracy. "o drawing is use,u+ un+ess it shows thein,or5ation correct+-.
2. Speed . Ti5e is 5one- in industr-. Work s5arter and +earn
to use techni0ues to speed up -our sketching and C)D drawings whi+e sti++ producing neat accurate resu+ts.
(. Legibility. ) drawing is a 5eans o, co55unicating with others so it 5ust 4e c+ear and +egi4+e. i/e attention todetai+s.
Things that 5a- see5 pick- and s5a++ as -ou are drawing 5a- 4e signicant and sa/e 5one- or e/en +i/es when the product is 4ui+t.
7. Neatness. !, a drawing is to 4e accurate and +egi4+e it 5ust a+so 4e c+ean.
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Drawing 8oca4u+ar-Drawing 8oca4u+ar-
• Drawing Lines
• Lettering
• Measure5ent S-ste5s
• Sca+e
• Tit+e 9+ocks
A B C
Tit+e 9+ock
55!nch
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
& S
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
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)L$)9ET &* L!"ES)L$)9ET &* L!"ES
Thick and Thin Drawing Lines
*reehand +ine techni0ue
Line st-+es
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*%EE)"D L!"ES*%EE)"D L!"ES The 5ain di:erence 4etween an instru5ent or C)D drawing and afreehand sketch is in the appearance o, the +ines. ) good ,reehand
+ine is not e3pected to 4e precise+- straight or e3act+- uni,or5 as is aC)D or instru5entdrawn +ine. *reehand +ines show ,reedo5 and/ariet-.
Freehand construction lines are very light, rough
lines. All other lines should be dark and clean.
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ood and $oor Techni0ueood and $oor Techni0ue
*%EE)"D L!"ES*%EE)"D L!"ES
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SKETC!" ST%)!T L!"ESSKETC!" ST%)!T L!"ESMost of the lines in an average sketch are straightlines. With
practice, your straight lines will naturally improve,ut theseasics may help you improve !uickly.
; o+d -our penci+ natura++- a4out 1< 4ack ,ro5 the point and appro3i5ate+- at a right ang+e to the +ine to 4e
drawn.
; Draw horionta+ +ines ,ro5 +e,t to right with a ,ree and eas- wrist and ar5 5o/e5ent.
; Draw /ertica+ +ines downward with nger and wrist 5o/e5ents.
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ST%)!T L!"E TipsST%)!T L!"E Tips
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SKETC!" C!%CLESSKETC!" C!%CLES
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ME)S=%EME"T S>STEMSME)S=%EME"T S>STEMS
=.S. Custo5ar- =nits
The Metric S-ste5
Dua+Di5ensioned
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D%)W!" SC)LED%)W!" SC)LEDrawing scale is the reduction or en+arge5ent o, the
drawn o4?ect re+ati/e to the rea+ o4?ect
%educed and En+arged Sca+e. Many drawings must be shown at reducedscale for the object to t on the paper.
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S$EC!*>!" TE SC)LE &" )S$EC!*>!" TE SC)LE &" )
D%)W!"D%)W!"
List the predo5inant drawing sca+e in thetit+e4+ock. @Courtes- o, D-no?et %esearch!nc.A
*or a part that is shownon the paper at ha+, itsactua+ sie the sca+e is
+isted in one o, thesethree wa-sB
SC)LEB 1B2SC)LEB 12SC)LEB .
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2. $%&'ECT!&"S2. $%&'ECT!&"S
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$%&'ECT!&"S$%&'ECT!&"S
To 5ake and interpret drawings -ou need to know how tocreate
pro?ections and understand the standard arrange5ent o,/iews.
>ou a+so need to 4e ,a5i+iar with the geo5etr- o, so+id o4?ectsand 4e a4+e to /isua+ie a (D o4?ect that is represented in a 2Dsketch or drawing.
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Edges and 8erticesEdges and 8ertices
dges
)n edge o, the so+id is ,or5ed wheretwo sur,aces intersect. Edges arerepresented in drawings 4- /isi4+e orhidden +ines.
!ertices) /erte3 @p+ura+ /erticesA o, a so+id
is ,or5ed where three or 5oresur,aces intersect..
Points and Lines) point is used to represent a +ocation in
space 4ut has no width height or depth.
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&"E8!EW D%)W!"S&"E8!EW D%)W!"S*re0uent+- a sing+e /iew supp+e5ented 4- notes anddi5ensionsis enough in,or5ation to descri4e the shape o, a re+ati/e+-si5p+e o4?ect.
"ote how thickness o, the 5ateria+ is gi/en as F.2 9%)SSG So an additiona+ /iew is not needed to di5ensiona++- gi/e the 5ateria+ thickness.
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$!CT&%!)L SKETC!"$!CT&%!)L SKETC!") pictorial sketch represents a "D ob#ect on a $D sheet o% paper 4- orienting the o4?ect so -ou can see its width height and depthin a sing+e /iew.
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Graphical projection is a protocol by which an image of an three-dimensional object is projected onto a planar srface withot theaid of mathematical calclation! sed in technical drawing.
"he projection is achie#ed by the se of imaginary projectors and projection plane.
$%&'ECT!&"S$%&'ECT!&"S
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$%&'ECT!&"S$%&'ECT!&"S9ehind e/er- 2D drawing o, an o4?ect is a space re+ationshipin/o+/ing the o4?ect and three imagined! things"
1. The o4ser/erHs e-e or station point
2. The p+ane o, pro?ection
(. The pro?ectors @a+so ca++ed /isua+
ra-s or +ines o, sightA.$erspecti/e $ro?ection
$ara++e+ $ro?ection
T pes o, $ro?ectionsT-pes o, $ro?ections
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T-pes o, $ro?ections T-pes o, $ro?ections There are two 5ain t-pes o, pro?ectionB perspective and parallel . These are 4roken down into su4t-pes as shown4e+owB
$ ? ti M th d$ ? ti M th d
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$ro?ection Methods$ro?ection Methods
The ,our principa+t-pes o,pro?ectionsB
a Mu+ti/iew 4 )3ono5etric c &4+i0ue d $erspecti/e
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(. &%T&%)$!C(. &%T&%)$!C
$%&'ECT!&"$%&'ECT!&"
@Mu+ti8iewsA@Mu+ti8iewsA
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8iews o, &4?ects or8iews o, &4?ects or
Multi#iewsMulti#iews) s-ste5 o, /iews or pro?ections. Each /iew pro/ides certain denitein,or5ation. *or e3a5p+e a ,ront /iew shows the true shape and sie o,
sur,aces that are para++e+ to the ,ront o, the o4?ect.
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Th Si S d d 8iTh Si St d d 8i
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The Si3 Standard 8iews The Si3 Standard 8iews)n- o4?ect can 4e /iewed ,ro5 si3 5utua++-perpendicu+ar directions
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%e/o+/ing the &4?ect to%e/o+/ing the &4?ect to
$roduce 8iews$roduce 8iews
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$rincipa+ Di5ensions$rincipa+ Di5ensions The three principa+ di5ensions o, an o4?ect are width heightand depth.
• The ,ront /iew shows on+- the height andwidth o, the o4?ect and not the depth.
• !n ,act an- principa+ /iew o, a (D o4?ect showson+- two o, the three principa+ di5ensionsI the
third is ,ound• in an ad?acent /iew.
• eight is shown in the rear +e,tside ,rontand rightside /iews.
• Width is shown in the rear top ,ront and4otto5 /iews.
• Depth is shown in the +e,tside top rightside• and 4otto5 /iews.
$ ? ti M th d$ ? ti M th d
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$ro?ection Method$ro?ection Method
$ro?ection o, an &4?ect
The out+ine on the p+ane o, pro?ection shows how the o4?ect appears to theo4ser/er. !n orthographic pro?ection ra-s @or pro?ectorsA ,ro5 a++ points onthe edges or contours o, the o4?ect e3tend para++e+ to each other and
perpendicu+ar to the p+ane o, pro?ection. The word orthographic 5eans atright ang+es.G
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orionta+ and $ro+eorionta+ and $ro+e
$ro?ection $+anes$ro?ection $+anesSpecic na5es are gi/en to the p+anes o, pro?ection. The ,ront
/iew is pro?ected to the ,ronta+ p+ane. The top /iew is pro?ected tothe horionta+ p+ane. The side /iew is pro?ected to the pro+ep+ane.
Th + 9Th + 9
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The +ass 9o3 The +ass 9o3&ne wa- to understand the standard arrange5ent o, /iews on thesheet o, paper is to en/ision a glass bo&.
!, p+anes o, pro?ection were p+aced para++e+ to each principa+ ,ace o, theo4?ect the- wou+d ,or5 a 4o3.
=n,o+ding the +ass 9o3=n o ng t e ass 9o3
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=n,o+ding the +ass 9o3=n o ng t e ass 9o3
To organie the /iews o, a (D o4?ect on a Jat sheet o, paperi5agine the si3 p+anes o, the g+ass 4o3 4eing un,o+ded to +ie Jat.
"ote the si3 standard/iews @,ront rear top4otto5 right side +e,tsideA.
Th + 9 = , +d dTh + 9 = , +d d
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The +ass 9o3 =n,o+ded The +ass 9o3 =n,o+dedLines e3tend around the g+ass 4o3 ,ro5 one /iew to another on thep+anes o, pro?ection. These are the pro?ectors ,ro5 a point in one
/iew to the sa5e point in another /iew.
h & h hi ? iTh & th hi $ ? ti
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The &rthographic $ro?ection The &rthographic $ro?ection The ,ront top and rightside /iews o, the o4?ect shown nowwithout the %olding lines.
" 8i"ecessar- 8iews
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"ecessar- 8iews"ecessar- 8iews
The top ,ront and rightside /iews
arranged together are ca++ed thethree regular views becausethe- are the /iews 5ost ,re0uent+-used.
A sketch or drawing should contain only the views neededto clearly and completely describe the object.
T 8iTwo 8iews
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Two 8iews Two 8iewsMan- o4?ects need on+- two /iews to c+ear+- descri4e their shape. !,an o4?ect re0uires on+- two /iews and the +e,tside and rightside
/iews show the o4?ect e0ua++- we++ use the rightside /iew.
&ne 8ie&ne 8iew
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&ne8iew&ne8iew&,ten a sing+e /iew supp+e5ented 4- a note or 4- +ettereds-54o+s is
Enough.
Choice o, *ront 8iewChoice o, *ront 8iew
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Choice o, *ront 8iewChoice o, *ront 8iew
The /iew chosen ,or the front view in this case is the side not thefront o, the auto5o4i+e.
$osition o, the Side 8iew$osition o, the Side 8iew
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$osition o, the Side 8iew$osition o, the Side 8iewSo5eti5es drawing three /iews using the con/entiona+arrange5ent wastes space.
idden Linesidden Lines
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idden Linesidden Lines Thick dark +ines represent ,eatures o, the o4?ect that are direct+-/isi4+e. Dashed +ines represent ,eatures that wou+d 4e hidden 4ehindother sur,aces.
Center+inesCenter+ines
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Center+inesCenter+ines'he centerline pattern is used to(
; show the a3is o, s-55etr- ,or a ,eature or part; indicate a path o, 5otion; show the +ocation ,or 4o+t circ+es and other circu+arpatterns
The center+ine pattern
is co5posed o, threedashesB one +ong dashon each end with ashort dash in the5idd+e.
C C & S$%ECEDE"CE &* L!"ES
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$%ECEDE"CE &* L!"ES$%ECEDE"CE &* L!"ES
) /isi4+e +ine a+wa-s takes precedence o/er
and co/ers up a center+ine or a hidden +inewhen the- coincide in a /iew @) and 9A.
) hidden +ine takes
precedence o/er acenter+ine @CA.
Center+ines continuedCenter+ines continued
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Center+ines continuedCenter+ines continuedCenter+ines @s-54o+B A are used to indicate s-55etrica+ a3es o,o4?ects or ,eatures 4o+t circ+es and paths o, 5otion.
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$RA%"&%E %'A(( )*R+ , 1
Ee.1 As Eample/ raw the three orthographic mlti#iews forthe following part