IsometricDrawing

Description

Isometric drawings use perspectiveto communicatealargeamount of information ina singledrawing. Isometric drawingsshowthreesides ofanobject,makingiteasier to better understandhow a finished object may look or howthe pieces ofthe object will fit together.Inthisactivity,students will draw an isometric drawing onapiece of paperwitha titleblock.Students will alsocontinuetopractise lineweights andlettering techniques.

LessonObjectives

The student willbeableto:

•Completea boardset-up

•Identify andappropriatelyuse drafting tools

•Create an isometric drawing of an object

•Differentiatelineweights

•Refine letteringtechniques

Assumptions

The student will:

•Havea basic knowledge of draftingtoolsand equipment

•Have a foundationalunderstandingofhowtoappropriatelyuse drafting equipment

•Havecreated a title block on which tocompletethis activity

Terminology

Borderortitleblocklines:thick,darklinesusedtocreateasolidborderaroundablankpage.

Draftingboard:aflat,smoothsurfaceusuallycoveredin vinyl towhichpaperisaffixed.Thedraftingboardhas square, paralleledgesthatallowa T-square toslideeasily.

Draftingbrush:usedtosweep away debrisfromadrawingsothefulldrawingisnotsmeared.

Erasershield:amicro-thinpieceofmetalwithcut-outsthatallowtheusertoerasedetailedsectionsofadrawingwithouterasingtherestofthedrawing.

Guidelines:thin,lightlines,drawnwhenusingtheletteringguideforevenlyspacedletters.

Isometricdrawing:atwo-dimensionaldrawingthatlooks3D.Thisdrawingwillshowthreesidesoftheobjectinoneviewandwillbecreatedusinglinesprimarilyat30and90degreesfromhorizontal.Whendrawingonpaper, you willusea30/60/90triangle.

Layoutlines:verylightlinesusedto layout measurementsbeforethosemeasurements aredrawninheavy,darklines.

Letteringguide:usedtoassistinthedrawingofuniformlinestodrawconsistent, evenlyspacedlettering.

Lineweight:thethicknessanddarknessofdrawnlines.

Maskingtape(draftingdots):holdsdrawingpaperand/orvellum tothedraftingboardsothepaperdoesnotshiftwhiledrawing.

Pencil:adrawing utensilwithamechanicalorsolidcore (lead).Leadsrangefromhardtosoft:6H,4H,2H,H,HB,2B,4B,6B.HisveryhardwithafinepointandBisextremelysoftwithabluntpoint.Ahardnessof2Hwillbeusedfortheseactivities.

Precisiondrawing:theactofcreatingdrawingswithspecializedtoolsandequipment.

Steelrule:astraightedgemadeofrigidmaterialanddivided intospecificincrements,foundbothinmetricandimperialunits.

Triangles(rightangleandisosceles):draftingguidesmadeofhard,clearplasticthatareusedtodrawlinesatverticalandsetangles (45°-90°-45°, 30°-60°-90°).

T-square:precisiondrawinginstrumentthatisusedasaguidewithotherdraftingequipment.The T-square hasa90°anglewheretheheadandbladeattach.

EstimatedTime

60–90minutes

RecommendedNumberofStudents

20, basedontheBCTechnology Educators’Best PracticeGuide

Facilities

•Regular classroom spacewithdesks/chairsforallstudents

•Drafting boardswould be ideal.Howeversmooth,clean,flat surfaces willalso suffice.

Tools

•T-square

•Steelrule

•Triangles(rightangle andisosceles)

•Eraser shield

•Draftingbrush

•Maskingtape(drafting dots)

•Draftingboard

•Letteringguide

•2H mechanical pencil

•Isometricdot paperfor practice

Materials

•Handoutforstudentswithinstructions(this could be directly from thisdocument—i.e.,printthetextundertheTeacher-ledActivity)

•Title-block drawingpage(createdinIntroductiontoTitleBlocksactivity)

•Isometricdot paperfor practice

•Wooden block usedin theScale and DimensioningandOrthographic Drawingactivities

Teacher-ledActivity:IsometricNotes

Anisometricdrawingisbased on threeaxesthatareequallyspacedapartat120°(Figure1).Lines that runparallel tothe axes are calledisometriclines. Linesthat are NOT parallel arecallednon-isometriclines.

Anisometricdrawing can be identifiedbyseveralfactors:

•Verticalplanes or edgesarestilldrawnvertically.

•Left andrightplanesaredrawnatanangleof 30° abovehorizontal.

•Nohorizontal lines are foundon isometrics.

Figure1Anisometric view.Isometricsshowathree-dimensionalobjectfromthree perspectivesin asingle drawing.

Teacher-ledActivity

Have studentssketch anobjectusingcorrect isometric standards.Labellingthe sides oftheobject with a sticky notemayassistnovicestodifferentiatebetweenthedifferentplanes.

Isometricpaper(includes vertical axesaswellas 30° axesalreadylaidout)isanexcellentwaytobegin.

1.Gatherallmaterials listed above.

2.Demonstrate:UsingtheT-squareandmaskingtape/draftingdots,align title-blocked papertoyour drafting boardandsecurely tape down(Figure2).

Figure2Securepapertoboard

3.Thethreedimensions oflength, width,andheightaredrawn alongthe isometric axesshowninFigure3.Thelengthsof objects runningparalleltotheseaxes can be drawntoscale.Lines atother angleswill not betoscale.

Figure3Height, width, andlength drawn alongisometric axes

4.Draw a small,six-pointedstar-shaped axis on the bottom corner ofyourpaper(Figure4).Theslopingaxesshould be drawnat a 30° angle from thehorizontal grid line.The verticalaxis ofthestarindicatesheight (H) or depth(D),andthe two slopingaxesindicate thelength

(L) and thewidth (W) oftherectangle.Theverticalaxiscanbeused as a referenceguidewhenmakinglines on yourdrawing.

Figure4Six-pointedstar-shapedaxis

5.Sketchthetopofthe block bydrawingtwolines,oneparallelto L andoneparallelto W(Figure5).

Figure5Sketchingthetopof theblock

6.Sketchtwolines,oneparallelto L andoneparallelto D asshowninFigure6.

Figure6Sketchingthesideof theblock

7.Sketch twolines,oneparallelto W andone parallel toD,tocompletethe outlineof therectangular block (Figure7).Beginwithlightlayoutlines so thatyou can makeany

necessary adjustmentsbeforedarkeningthem.Thefinishedisometricsketchisdrawnwithdark object linesinFigure 8.

Figure7Full outlineofrectangularblockFigure8Isometricobject

8.Completethe activity byfillinginthetitle block asfollows:

ACTIVITY # 6 / NAME
DATE
ISOMETRIC / SCALE OF DRAWING 1:1
PAGE 1 OF 1

ExtensionActivity

Furtherdrawing practice creatingmoreisometricobjects,usingdifferentwooden cut-outshapes.

Assessment

•Student participation indiscussion/demonstration

•Completionof drawing with overall neatness:

–Linesare concisely drawn.

–Isometric object is accurateandproportionalto page.

–Borderlines cross toensure closed corners.

–Letteringisdoneto a highquality(alluppercase).

–Title block isfilledout correctly withappropriateinformation.

AppendixAcknowledgment

© Camosun College.TradesAccess Common Core:CompetencyD-3:ReadDrawingsandSpecifications(pp.79–83).TheTrades Access Common Core resourcesarelicensedundertheCreativeCommons Attribution 4.0 Unported Licence ( otherwise noted.

Appendix

Makeisometricsketchesofsimplerectangularobjects

Isometricsketchesareusefulbecausetheyareeasytodrawandclearlyrepresentanobject orsystem.Thisclaritycomesfromusingdirectionallinestorepresentthethreedimensionsoflength,width,andheight,muchlikeapicture.

Constructionmethods

Thefollowingstepsexplainhowtodrawanisometriccube.Thethreedimensionsoflength,width,andheightaredrawnalongtheisometricaxesshowninFigure8.Thelengthsofobjectsrunningparalleltotheseaxescanbedrawntoscale.Linesatotherangleswillnotbetoscale.

Height

Figure8—Isometricaxes

Drawasmallstar-shapedaxisonthebottomcornerofyourgridpaper.Theslopingaxesshouldbedrawnata30°degreeanglefromthehorizontalgridline.Theverticalaxisofthestarindicatesheight(H)ordepth(D),andthetwoslopingaxesindicatethelength(L)andthewidth(W)oftherectangle.Theverticalaxiscanbeusedasaguidewhenmakinglinesonyourdrawing.NoticewehavelabelledthepointsonthestarinFigure9.Theselabelscanchangedependingontheviewthatyoumaywantwhendrawingastationaryobject.Thebottomtwohorizontalpointsindicatetheviewthatisbeingdrawn.Inthiscasewewouldbecreatingafront-rightview.

Toporplan

LeftBack

30º30º

FrontRight

Bottom

Figure9—Step1:Isometricguideforfront-rightview

8“Download for free at

SkillsExploration10–12

Sketchthe top oftheblock by drawingtwolines,oneparallelto L andoneparallel toW (Figure10).

Figure10—Step2:Isometricviewoftopsurfaceofarectangularblock

Sketchtwolines,oneparalleltoLandoneparalleltoDasshowninFigure11.

Figure11—Step3:LinesparalleltoLandD

Sketchtwolines,oneparalleltoWandoneparalleltoD,tocompletetheoutlineoftherectangularblockasshowninFigure12.Beginwithlightconstructionlinessothatyoucanmakeanynecessaryadjustmentsbeforedarkeningthem.ThefinishedisometricsketchisshowninFigure13.

Figure12—Step4:Completedoutlineofrectangularblock

Figure13—Completedisometricsketch

Sketchingirregularshapeswithisometriclines

Notallrectangularobjectsareassimpleastheblockyouhavejustsketched.Sometimestheshapesareirregularandhavecut-outsectionsorsomesideslongerthanothers.Allrectangularobjectscanbefittedintoaboxhavingthemaximumlength(L),width(W),anddepth(D).Beginbysketchingalightoutlineofabasicboxthatisthesizeoftheobjecttobedrawn.

Asanexample,considertheobjectshowninthethree-vieworthographicsketchinFigure14. Toproduceanisometricsketchofthisobject,youneedtofindthemaximumL,W,andDforthecontainingbox(Figure14).Inthiscase:

L=5gridspacesW=3gridspacesD=3gridspaces

Top

W=3
L=5 / H=3

Side

Figure14—Orthographicviews

Front

Sketchalightoutlineofthebasicrectangularboxtotherequiredsize,asshowninFigure15.

Top

D=3units

Front

L=5units

Side

W=3units

Figure15—Basicoutline

Thefrontviewshowstheoutlinemostclearly.Placethisviewonthefrontsurfaceoftheisometricbox.UsethedimensiongiveninthefrontviewofFigure14andmarkthenumberofunitsindicatedalongtheaxesLandD(Figure16).

Figure16—Locationofmarksonaxes

LightlysketchlinesparalleltotheLandDaxesfromthemarkedpointsonthefrontsurface(Figure17).Thestepoutlineisdrawnmoreheavilytoemphasizetheprofileoftheobject,onceyouaresureyoursketchiscorrect.

Figure17—Locationofmainfeatures

Figure18—Locationofoutersurfaces

Sketchinaseriesoflinesparalleltotheaxes(L,W,andD)fromthecornersnumbered1to7(Figure18).TheselinesestablishthesteppedoutlineasshowninFigure19.

Whenyouaresureyourisometricsketchiscorrect,eraseallunnecessaryconstructionlinesanddarkentheobjectlines.YourcompletedsketchoftherectangularobjectshouldbesimilartothatinFigure20.

Figure19—Internalfeatures

Figure20—Completedsketch