chapter 15 pictorial drawings engineering drawing and design engineering drawing and design seventh...

Chapter 15Chapter 15

Pictorial Drawings

EngineeringDrawing and Design

EngineeringDrawing and DesignSeventh EditionSeventh Edition

15-1 Pictorial drawings-axonometric, oblique &

perspective• Used to explain complicated engineering

drawings to the untrained**• Help with design work in space• Train new employees in the shop• Speed up & clarify assembly of a machine• Transmit ideas• Aid in developing the power of visualization

PICTORIAL DRAWINGS

AXONOMETRIC PROJECTION

FRONT VIEW SIDE VIEW

PICTORIAL DRAWINGS

OBLIQUE PROJECTION

FRONT VIEW SIDE VIEW

PICTORIAL DRAWINGS

PERSPECTIVE PROJECTION

FRONT VIEW SIDE VIEW

Axonometric Projection

• The lines of sight are perpendicular to the plane of projection, but the 3 faces of a rectangular object are all inclined to the plane of projection*

• 3 forms of Axonometric Projection*– Isometric: 3 principal faces and axes are equally

inclined to the plane of projection– Diametric: 2 of the 3 are equally inclined– Trimetric: all 3 faces and axes of the object make

different angles with the plane of projection

PICTORIAL DRAWINGS

AXONOMETRIC PROJECTION

PICTORIAL DRAWINGS

TYPES OF AXONOMETRIC DRAWINGS

PICTORIAL DRAWINGS

TYPES OF AXONOMETRIC DRAWINGS

PICTORIAL DRAWINGS

TYPES OF AXONOMETRIC DRAWINGS

PICTORIAL DRAWINGS

AXONOMETRIC PROJECTION

USE OF THIS SET ENABLES YOU TO SHOW THEOBJECT FROM THESE 48 VIEWPOINTS.

PICTORIAL DRAWINGS

TYPES OF AXONOMETRIC DRAWINGS

USE OF THIS SET ENABLES YOU TO SHOW THEOBJECT FROM THESE 144 VIEWPOINTS.

Isometric drawings• Revolving the object at an

angle of 45⁰ to the horizontal so that the front corner is toward the viewer and then tipping the object up or down at 35⁰ 16’

• 3 visible faces appear equal in shape & side faces are at 30⁰ to horizontal*

• Isometric grid paper & ellipse templates aid sketching

• Vertical axis (height)• Left & right axes 30⁰ from

horizontal (length & width)• All lines drawn true length*• Hidden lines omitted• Nonisometric lines are

sloping surfaces and are created by locating their endpoints

15-2&3: Isometrics continued

• Circles on any of the 3 faces appear as an ellipse

• Isometric ellipse templates

• Fillets & rounds• Threads• Break lines• Isometric assembly

drawings

• Isometric sections are taken on a plane parallel to the face of one of the cubes

• Section lines are shown at 60⁰ with horizontal or in a horizontal position depending on where the cutting plane line is located

PICTORIAL DRAWINGS

ISOMETRIC AXES AND PROJECTION

PICTORIAL DRAWINGS

ISOMETRIC AXES AND PROJECTION

PICTORIAL DRAWINGS

DEVELOPING AN ISOMETRIC DRAWING

PICTORIAL DRAWINGS

SEQUENCE IN DRAWING AN OBJECT HAVING NONISOMETRIC LINES

PICTORIAL DRAWINGS

ORIENTING THE DIMENSION LINE, ARROWHEAD, AND EXTENSION LINE

PICTORIAL DRAWINGS

DIMENSIONING AN ISOMETRIC DRAWING

PICTORIAL DRAWINGS

ISOMETRIC GRID PAPER

PICTORIAL DRAWINGS

CURVED SURFACES IN ISOMETRIC

PICTORIAL DRAWINGS

SEQUENCE IN DRAWING ISOMETRIC CIRCLES

PICTORIAL DRAWINGS

DRAWING CONCENTRIC ISOMETRIC CIRCLES

PICTORIAL DRAWINGS

DRAWING ISOMETRIC ARCS AND CIRCLES

PICTORIAL DRAWINGS

ISOMETRIC SECTIONING

PICTORIAL DRAWINGS

ISOMETRIC SECTIONING

PICTORIAL DRAWINGS

CONVENTIONAL BREAKS IN ISOMETRIC

PICTORIAL DRAWINGS

FILLETS AND ROUNDS IN ISOMETRIC

PICTORIAL DRAWINGS

THREADS IN ISOMETRIC

15-4 Oblique projection

• This method is based on the procedure of placing the object with 1 face parallel to the frontal plane and placing the other 2 faces on oblique (receding) planes to left or right, top or bottom, at a convenient angle

• 3 axes of projection: horizontal, vertical, receding

• One face of the object is shown without distortion

Oblique projection: Cavalier and Cabinet Methods

• In cavalier all lines are made to their true length measured on the axes of projection

• Oblique sketching paper

• In cabinet, the lines on the receding axis are shortened by ½ their true length to approximate more closely what the human eye would see

• Cabinet is the more commonly used form especially for circles & arcs

PICTORIAL DRAWINGS

TYPES OF OBLIQUE PROJECTION

PICTORIAL DRAWINGS

OBLIQUE SKETCHES

PICTORIAL DRAWINGS

OBLIQUE PROJECTION

PICTORIAL DRAWINGS

DIMENSIONING AN OBLIQUE DRAWING

PICTORIAL DRAWINGS

OBLIQUE SECTIONS

PICTORIAL DRAWINGS

OBLIQUE ROUNDS AND FILLETS OBLIQUE BREAKS

OBLIQUE THREADS

15-6 Parallel or 1-point perspective

• Perspective is a method of drawing that depicts a 3-D object on a flat plane as it appears to the eye

• More realistic than axonometric or oblique• Main elements of a perspective drawing– Picture plane (plane of projection)– Station point (position of observer’s eye)– Horizon (imaginary horizontal line taken at eye level)– Ground line (base line off the picture plane & object)

PICTORIAL DRAWINGS

PERSPECTIVE PROJECTION

PICTORIAL DRAWINGS

PERSPECTIVE DRAWINGS

RECORDING THE PICTURE ON THE PICTURE PLANE

PICTORIAL DRAWINGS

TYPES OF PERSPECTIVE DRAWINGS

PICTORIAL DRAWINGS

ONE-POINT PERSPECTIVE

PICTORIAL DRAWINGS

ANGULAR, OR TWO-POINT PERSPECTIVE

PROJECT POINTS A AND B DOWN FROM PICTURE PLANE TO LOCATE POSITIONS OF LEFT AND RIGHT VANISHING POINTS

PICTORIAL DRAWINGS

ANGULAR PERSPECTIVE GRID

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