The document discusses freehand sketching techniques that are important for engineers and designers. It states that freehand sketching allows engineers to initially conceive 3D objects on paper and convey their ideas to others. Good practice in freehand sketching helps engineers think about designs rather than focusing on drawing methods. The basics of sketching straight lines, circles of different sizes, and orthographic views from pictorials are covered. Guidelines for materials, marking points, and proportion are provided to help sketch objects accurately without using scales.

1. FREEHAND SKETCHING
Part I
Prof.T.JEYAPOOVAN
Department of Mechanical Engineering
Hindustan Institute of Technology and Science
Chennai-603103, India
www.EGlive.in

2. Freehand Sketching
• An engineer or designer conceives an idea of a non-existing
object three dimensionally, which can be conveyed to
another person only through a drawing.
• Initially the object is sketched on paper as an isometric or
perspective drawing, then that will be given dimensions.
• Good practice in freehand sketching helps the engineer to
think about the new design rather than to think about the
method of preparing the drawing.
• When the designer’s mind thinks an idea that is sketched by
him in freehand. An engineer who has a thorough idea in
isometric and orthographic projections can prepare the
sketches easily.
www.EGlive.in

3. Freehand Sketching Practice
• For freehand sketching
practice, soft grade pencil
(HB), eraser and paper are
required.
• Papers with thin cross-section
guidelines (ruled paper) may
be used for sketching which
helps the inexperienced
person to draw straight lines
satisfactorily.
www.EGlive.in

4. Sketching a straight line
• Mark the end points of the line to
be sketched.
• Observe the two points carefully
and make some trial movements
between the points without
sketching any line.
• Sketch light and thin trial lines
connecting the two points.
• Complete the straight line by
drawing a straight and dark line
over the thin line.
www.EGlive.in

5. Sketching a small circle
• Sketch the center lines for the
circle horizontally and
vertically and mark four points
on them approximately equal
to the radius of the circle.
• Sketch the light circle passing
through these points.
• Complete the circle with dark
lines.
www.EGlive.in

6. Sketching a big circle
• Sketch the center lines for the
circle horizontally and vertically
and mark four points on them
approximately equal to the
radius of the circle.
• Sketch more diagonal lines in
addition to the center lines for
big circle.
• Sketch the light circle passing
through these points.
• Complete the circle with dark
lines.
www.EGlive.in

7. Sketching Orthographic views from
pictorial view
• Observe the shape of the object carefully. Sketch thin
and light rectangles for the views to be drawn.
• Sketch and complete the views, then darken the lines.
www.EGlive.in

8. Sketching Orthographic views from
pictorial view
• Observe the shape of the object carefully. Sketch thin
and light rectangles for the views to be drawn.
• Sketch and complete the views, then darken the lines.
www.EGlive.in

9. Sketching Orthographic views from
pictorial view
• Observe the shape of the object carefully. Sketch thin
and light rectangles for the views to be drawn.
• Sketch and complete the views, then darken the lines.
www.EGlive.in

10. Sketching Orthographic views from
pictorial view
• Observe the shape of the object carefully. Sketch thin
and light rectangles for the views to be drawn.
• Sketch and complete the views, then darken the lines.
www.EGlive.in

11. Tips to draw Freehand sketching
• The visible and invisible edges are usually identified
through visualization and understanding.
• Note that the dimensions of the lines sketched in the
views are taken in proportion to the dimensions of the
object.
• Sketches are not prepared to scale/actual dimensions.
• The rectangle to enclose the views can be omitted after
practicing many sketching exercises with an eye on
taking the proportional dimensions of the object.
• Complete the sketching of the object by drawing dark
lines.
www.EGlive.in

12. REFERENCE BOOKS
1. Jeyapoovan T, “Lesson Plans for Engineering
Graphics”, 2010, Vikas Publishing House Pvt
Ltd, New Delhi.
2. Jeyapoovan T, “Engineering Drawing and
Graphics”, 2011, Vikas Publishing House Pvt
Ltd, New Delhi.
www.EGlive.in

13. End of Lesson 14
Thank You
www.EGlive.in