ENGINEERING DRAWING SKKK 1021 ISOMETRIC DRAWING Agus Arsad, Azizul Azri Bin Mustaffa 10/2/2012 1
LEARNING OUTCOMES ISOMETRIC DRAWING It is expected that students will be able to: Understand the significance of isometric drawing Apply the basics method of isometric drawing 10/2/2012 2
ISOMETRIC DRAWING INTRODUCTION SIGNIFICANCE TRUE LENGTH BASIC METHOD 10/2/2012 3
INTRODUCTION Isometric drawing method shows the drawing in 3-D The real shape of an object can be easily interpreted by using isometric drawing The construction of an isometric drawing can be made by viewing the object from certain angle and directions. 10/2/2012 4
SIGNIFICANCE In this Chapter, you will be constructing isometric drawings from given orthographic projections of an object. Isometric drawing is important to engineering designers as the drawing shows clearly what that has been designed It is also useful for equipment designers as they can easily interpret the method of construction of an object or equipment. This type of drawing also can cope with beginners of someone who has no basics in engineering drawing unlike orthographic drawing. 10/2/2012 5
TRUE LENGTH Every measurements that are transferred to the isometric drawing is in its true length of the object However, only vertical & horizontal lines in orthographic drawing can be transferred directly to isometric drawing. Inclined, oblique lines, circles and others however cannot be transferred directly and must be drawn using certain techniques 10/2/2012 6
Distance in Isometric Drawing True-length distances are shown along isometric lines. Isometric line is the line that run parallel to any of the isometric axes. Nonisometric lines Isometric axes 10/2/2012 7
BASIC METHODS Isometric drawing is built on 3 main axis namely the vertical axis and two 30 degrees axis from a horizontal line to the left and right of the vertical axis Vertical Axis 30 degrees axis 30 degrees axis Horizontal line 10/2/2012 8
Isometric Drawing and Scale Isometric drawing is a drawing drawn on an isometric axes using full scale. Isometric projection (True projection) Isometric drawing (Full scale) Foreshorten Full scale 10/2/2012 9
Sketch from an actual object 1.Place the object in the position which its shape and features are clearly seen. 2. Define an isometric axis. 3. Sketching the enclosing box. 4. Estimate the size an and relationship of each details. 5. Darken all visible lines. 10/2/2012 10
Sketch from an actual object STEPS 1. Positioning object. 2. Select isometric axis. 3. Sketch enclosing box. 4. Add details. 5. Darken visible lines. Note In isometric sketch/drawing), hidden lines are omitted unless they are absolutely necessary to completely describe the object. 10/2/2012 11
H Example 1 : Object has only normal surfaces Top View Regular H Top Front Side Front View Side View W D W D Front Side Bottom View Reverse Bottom 10/2/2012 12
Example 2 : Object has inclined surfaces H D y Nonisometric line y x W Front View x 10/2/2012 13
y Example 3 : Object has inclined surfaces x C B A x x B x C A y C B A Nonisometric line 10/2/2012 14
x Example 4 Regular y C E B D F Front View A B Reverse C D A F E 10/2/2012 15
Circle & Arc in Isometric In isometric drawing, a circle appears as an ellipse. Sketching Steps 1. Locate the center of an ellipse. 2. Construct an isometric square. 3. Sketch arcs that connect the tangent points. 10/2/2012 16
Circle & Arc in Isometric Four-center method is usually used when drawn an isometric ellipse with drawing instrument. Sketching Steps 1. Locate the center of an ellipse. 2. Construct an isometric square. 3. Construct a perpendicular bisector from each tangent point. 4. Locate the four centers. 5. Draw the arcs with these centers and tangent to isometric square. 10/2/2012 17
Example 5 10/2/2012 18
Irregular Curve in Isometric Steps 1. Construct points along the curve in multiview drawing. 2. Locate these points in the isometric view. 3. Sketch the connecting lines. 10/2/2012 19
END OF CHAPTER 5 10/2/2012 20