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Freehand sketchingCheckpoint 1.2Practice sketching a multi-view on a plainA4 drawing paper and rectangular gridpaper. Then explain the difference betweendrawing sketches on a plain paper and ongrip paper.Practice pictorial sketches on isometric andperspective grid papers.movement. Whenever possible sketch lines in adirection away from the body. As you sketch, rotate the pencilslightly between the thumb andfingers. This helps to preserve thesharpness of the pencil point and tomake uniformly thick lines. Because more freedom of movementis necessary when sketching, avoidfastening the paper to the workingsurface. The paper should be free tomove across the working surface asthe sketch is developed. Final lines on sketches should bebold, dark, and clean-cut. Straight lines should be drawn withminimum waviness. When sketching, avoid using ragged, overlaping strokes.1.5. Fundamentals of SketchingThe chief difference between an instrumentaldrawing and a freehand sketching lies in thecharacteristics of the technique of the lines.A good freehand line should not be rigidlystraight or exactly uniform, as an instrumental line. The effectiveness of an instrumentalline lies in exacting uniformity, while thequality of freehand lines lies in its freedomand variety.Good sketches constitute the followingtechniques. 8When sketching hold the pencilloosely and at a greater distancefrom the pencil point than in normalwriting. This distance may rangefrom about 3 to 5cm. Eye-handcoordination and muscle control areimportant and come with practice. During sketching short lines, usefinger movement keeping the wriststationary. When sketching longer lines, useless finger action with a stiffer arm1.5.1 Sketching Lines1. Straight LinesSince most sketches consist mainly ofstraightlines(horizontal,vertical,andinclined lines), it is important for you tolearn the simple techniques involved insketching these lines.

1 Free hand SketchingThe following steps are recommendedfor sketching straight line:Step 1: Mark the end pointsStep 2: Make a few trial motions betweenthe marked points to adjust theeye and hand to thecontemplated line.Step 3: Sketch a very light line betweenthe points by moving the pencilin two or three sweeps. Whensketching the trial line, the eyeshould be on the point towardb. Vertical LinesVertical lines are usually drawn from top tobottom, with finger and wrist movements,you should be able to develop enough skill todraw uniformly spaced parallel vertical lines.The edge of the drawing surface can be usedfor this as well as demonstrated inFig.1.10(b).c. Inclined linesInclined lines may be made to conform indirection to horizontal or vertical lines byturning the paper slightly (Fig.1.10 (c)).which the movement is directed.Step 4: Darken the finished line, keepingthe eye on the pencil point onthe trial line. The final line,replacing the trial line, should bedistinct,black,uniform,andstraight.a) Horizontal strokesb) Vertical strokesFig. 1.9 Steps in sketching a straight linea. Horizontal LinesThe normal way to draw parallel horizontallines is from left to right for right-handedpeople or right to left for left-handed people.c) Inclined strokesFig. 1.10 Freehand sketching techniquesYou should be able to develop enough skill tod. Sketching Border Linesdraw many evenly spaced horizontal linesBorder lines are a combination of verticaland horizontal lines. Therefore, they can besketched in the manner discussed before.9while leaving uniform spaces between thelines (See Fig.1.10 (a)).

Freehand sketchingFig. 1.11 Sketching a border lineThe following steps may befollowed to sketch boarderline easily;Step 1: Begin by aligning the edgeof the paper with that of theboard.Preventthepaperfrom sleeping by one handwhileholdingthepencilfirmly by the other hand asshown in Fig.1.11 (a).Step 2: Use the idle fingers of thehand holding the pencil as aguide against the edge of theboard (Fig.1.11 (b)).Step 3: Then slowly sketch theline pulling the pencil towardyou (Fig. 1.11 (c)). Here youneed not to sketch a trial line;instead produce a final boldline at the first stroke.Checkpoint 1.3Sketching horizontal, vertical andinclined linesPracticesketchinghorizontal,vertical and inclined lines on a plainsheet of A4 size paper. Sketch aboutten more parallel lines spaced by eyeabout 15mm apart. Try to keep thelines reasonably parallel.Sketching boarder linesSketch several differently spacedboarder lines around the edges of aplain sheet of A4 size paper. Try toproduce neat square corners wherethe lines intersect. Avoid extendingone line beyond another.2. Curved lines1. Have you ever sketched a circle? Howaccurate were you?2. What method do you suggest for accuracy?Curved lines are identified as circles, arcs,ellipse or irregular curves.a. Sketching CirclesCircles can be sketched by using lightguidelines along with centerlines. Since it10

1 Free hand Sketchingis difficult to draw a freehand circle inone continuous line, short arcs are drawnusing the guidelines.The recommended steps to drawcircles are given below.Sm all sizes lip to 25 m m diam etersStep 1Step 2Step 1: Sketch a center line bydrawing a horizontal and avertical line that intersect atthe center of the desiredcircle.Estimate and mark off theradius distance from thecenterpoint on each side ofthe centerline shown in step 1of Fig. 1.12.Step 2: Sketch one quarter of thecircle lightly and then sketchthe other quarter of the circleas shown in step 2 and 3 ofFigure 1.12.Step 3: Sketch the other half ofthe circles in the same manner.Darken the finale circle andchange the light horizontal andverticalconstructionlinesintersecting at the center of thecircle into centerlines as shownin step 4 of Fig.1.12.Step 3Step 4Fig. 1.12 Sketching a circle with diametergreater than 25mmLarge Sizes Greater Than 25 mmDiameterIf the size of the circle is large (greater than25mm diameter) the number of constructionlines used is increased to mark more numberof points on the circle. For example, a circleis sketched as shown in Fig. 1.13 by usingfour construction lines intersecting at thecenter of the circle. By marking off the radiuson each of these lines, eight points are found.These points are joined to sketch therequired circle. The sketching process of acircle is simpler when there are morenumber of points.11

Freehand sketchingb. Sketching ArcsAs an arc is part of a circle, sketching of arcsis similar to that of the circles.Steps to sk etch an arcStep 1: Sketch construction lines intersecting at the center of the arc;more number of constructionlines may be necessary forlarge size arcs.Fig. 1.13 Sketching a circle with diametergreater than 25mmWhen sketching even larger circles, sketch aconstruction square box whose side length isequal to the diameter of the circle asillustrated in Fig. 1.14. This box will help tomake the roundness of the circle as perfect aspossible.Step 2: Mark the radius of the arc on allconstruction lines.Step 3: The marked points are joined tocomplete the arc.Sketching of arcs of different sizes at variousconditions are illustrated in Fig. 1.15.(a)(b)(c)Step 1Fig. 1.14 Sketching a large circle(d)Step 2Checkpoint 1.4Sketching circlesOn an A4 paper sketch as manycircles as you can. Use the samepoint as a center to all circles.Start with a circle of 10mmdiameter.(e)(f)Step 3Fig. 1.15 Sketching arcs12(g)

1 Free hand SketchingCheckpoint 1.5complete the ellipse. Lightly all lines andheavy in the final ellipse.Sketching arcsOn an A4 drawing paper copy thearcs shown in Fig.1.15 to anyconvenient size.Sketching EllipsesIf a circle is viewed obliquely, it appears asan ellipse. With a little practice, you canlearn to sketch small ellipses with a free armmovement. Hold the pencil naturally, restthe weight on the upper part of the forearm,and move the pencil rapidly above the paperin the elliptical path desired; so lower thepencil so as to describe several lightoverlapping ellipses, as shown at I and heavyin the final ellipse II.Fig. 1.17 Sketching ellipse with light enclosingrectangleCheckpoint 1.6Sketching ellipsesPractice sketching ellipses on aplain sheet of A4 size paperwhose major and minordiameters are 50mm and 30mmrespectively.1.5.2 Dividing Lines and AreasEquallyFig. 1.16 Sketching an ellipse with free armmovementAnother method is to sketch lightly theenclosing rectangle, Fig.1.17 (I) mark themidpoints of the sides, and sketch lighttangent arcs, as shown. Then, Fig.1.17 (II)The beginner must recognize the importanceof being able to estimate comparativerelationships between the width, height, anddepth of an object being sketched. Thecomplete problem of proportioning a sketchalso involves relating the estimated13

Freehand sketchingdimensions for any component parts, such asslots, holes, and projections, to the over-alldimensions of the object. This is not thepractices of attempting to estimate actualdimensions.To become proficient at sketching one mustlearn to recognize proportions and be able tocompare dimensions "by eye" until one isable to do so. One cannot really "think withones pencil". Some people can develop akeen eye for proportion with only a limitedamount of practice and can maintain theseestimated proportions when making theviews of a sketch.1. Dividing a line into equal partsTo divide a line into any even num berof equal parts follow the follow ingsteps;Step 1: Estimate the mid-point of theline.Step 2: Estimate the mid points ofeach half.Step 3: Then estimate the mid pointsof the resulting four parts ofthe line and so on.However, you should practice estimatingone-third, one-fifth and one-seventh of shortlines to be able to divide a line into three,five, seven, or a multiple of them. Forexample, to divide a line into ten equal parts,start by estimating the midpoint of the line.Then you should estimate the one-fifth of14each half and mark the division points allover the line. Figure 1.18 shows the stepsinvolved in dividing a line into four equalparts.Given lineStep 1Estimate the centerof the lineStep 2Estimate the centerof each halfFig. 1.18 Dividing a line into four partsCheckpoint 1.7Dividing a line into a requirednum ber of partsSketch four horizontal lineswhich are 100mm long each ona plain sheet of A4 size paper.Carefully divide the first lineinto three equal divisions, thesecond line into five equaldivisions, the third line intoseven equal divisions, and thefinal line into eight equaldivisions.

1 Free hand Sketching3. Dividing the Area of a Rectangle2. Dividing the Area of a TriangleTo divide a triangular area into anynum ber of equal areas follow thefollow ing steps;Step 1: Start by dividing the sides ofIn order to divide the area of a rectangle, itssides should be divided first. Fig.1.20 one-third,inone-the triangle into any number offourth, and one-fifth of a side of a rectangle.parts as discussed above.The mid-point of a rectangle is the point ofStep 2: Then sketch lines by connectingintersection of the diagonals. A line sketchedthe vertex opposite to this sidethrough this point that is perpendicular toandthedivisionpointstodivide the triangle into equalareas.any side will establish the mid-point of thatside. To determine a distance that is equal toone fourth the length of a side, the quarterpoint may be located by repeating thisprocedure for the small rectangle representting the upper left-hand quarter of ABCD.a)b)a)c)Fig. 1.19 Dividing the area of a triangleCheckpoint 1.8Dividing the area of a triangleSketch a triangle whose sides are60mm, 70mm, and 90mm long.Divide it into six equal areas asshown in Fig 1.19.b)Fig. 1.20 Method of proportioningthe area of a rectangle15

Freehand sketchingCheckpoint 1.9Dividing the area of a rectangleSketch a rectangle whose sidesare about 100mm and 50mmlong. Divide its area into 10 equalrectangles.a)b)1.5.3 Sketching AnglesActivity 1.1 How can you estimate a given angle?Discuss and come with practical ideas topresent in group.One of the important sketching skills is theability to approximate a required angle. Asc)d)Fig. 1.21 Sketching approximate angleillustrated in Fig. 1.21, a 90 angle can beapproximatedbysketchingtwonearlyperpendicular lines as shown at Fig 1.12 (a).To sketch a 45 angle, sketch a square andconnect its opposite corners as shown at (b).To sketch a 30 angle, sketch a square and anCheckpoint 1.10Sketching anglesSketch 7 , 15 , 30 , 45 , and 90 angles whose sides are all 50mmlong.arc inside the square as shown at (c). Then,divide the arc into three equal parts andconnect the division points to the vertex ofthe angles. Similarly, a 15 angle can beapproximated by dividing the arc into sixequal parts as shown at (d). Different anglescan be constructed by bisecting angles thatcan easily be approximated. For example, a7 angle can be approximated by bisecting a15 angle. A 22 angle can be approximatedby bisecting a 45 angle.161.5.4 Sketching the Given ObjectsAs stated in section 1.7, in the sketch of anobject, the relative proportions of its primarydimensions (width, height, and depth) aremore important than their actual physicalsizes. A proportion is the ratio between anytwo dimensions of an object. The mostimportant rule in freehand sketching is tokeep the sketch in proportion.

1 Free hand Sketching1. Proportioning Large Objects2. Multi-view SketchingIn sketching from an actual object, you canThere are two recommended procedures foreasily compare various distances on thelaying out multi-view sketches: The outside-object by using the pencil to comparein method and the inside-out method. Bothmeasurements as shown in Fig. 1.22. Bythese methods use construction boxes toholding the pencil between the eye and thefacilitate the sketching process.object, one end of the pencil can be made tocoincide with one end of the object and thenthe thumb is moved along the pencil until itcoincides with the other end of the object.The length may then be used to obtain therelative proportions of the object. Whiledoing this, do not change your position, andalways hold your pencil at arm’s length. Thelength sighted can then be compared insimilar manner with any other dimension ofthe object.Fig. 1.22 Method of obtaining proportionswhen sketching large objectsa) Outside-in MethodThis method is illustrated in Fig 1.23. Thefirst step is to block in the main out line ofthe given object to a desired scale. Theblocking of details follows. Finally, the linesrequired to form the object are darkened.This method is particularly useful for objectswhose outline is made up of straight lines.Activity 1.21. Sketch a simple object from your class room,for example table or chair and show yourinstructor.2. Form a group and share ideas on the conceptof proportion. After this choose a groupleader and let the group leader share yourideas to the other groups, similarly let theother group leader come to you and presentthe idea of others.As you have seen in grade 11 text, projectioncan be classified into parallel and perspective projection. Multi-view, isometric andoblique projection use parallel projection. Inthe following section sketching of eachprojection will be discussed.17

Freehand sketchingb) Inside-out methodGiven objectIn this method, as its name implies,construction is done from inside out. That is,no blocking of the object as a whole isnecessary. Rather starting from a singledetail, construction continues until all detailsare over. Finally, the desired lines aredarkened. This method is illustrated in Fig.1.24.Step 1Sketch center lines and main constructionbox using proportional distances at thedesired enlarged size.This face is trueStep 1Sketchcenterlinesandmainconstruction box using proportionaldistances at the desired enlarged size.Step 2Block in details of the object proportionaldistanceStep 3Darken the final objectFig. 1.23 sketching an object to a reducedscale using the outside-in method18Step 2Block in other details andmark off radii usingproportional distancesStep 3Darken final object

1 Free hand Sketching3. Pictorial sketching1. Recall the types of pictorial drawings youknow from grade 11 parts.2. How do you think pictorial drawing can bedone by sketching?a)b)c)Pictorial sketching is used for preparingpictorial drawings that shows all the threedimensions of an object: width, height anddepth. Sales engineers may frequentlyinclude pictorial sketches with orthographicsketches when preparing field reports on theneeds and suggestions of the firm’scustomers. Students may use pictorialsketches as an aid in visualizing andorganizing problems.d)Fig. 1.24 Sketching an object to a magnifiedscale using the inside – out methodOblique: RecedingParallel linesAxonometric: RecedingParallel lines(a)(b)Check point 1.11Sketch the view of an objectSketch the three views of theobjects shown in Figure (a)and (b) to any convenientmagnified scale.Perspective: RecedingConverging lines(c)a)b)Fig. 1.25 Sketch the three types of pictorialsketches19

Freehand sketchingThe three principal types of pictorialsketches are: Oblique, Axonometric, andPerspective sketches. These forms areillustrated

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