ENGINEERING DRAWING

Oblique and Isometric Drawings

Review Learning ObjectivesSketch pictorials of an object (either oblique or isometric) given orthographic views of the objectSelect the best orientation of an object shown in pictorialDefine what makes a drawing a: cavalier oblique, cabinet oblique, isometric, axonometric, perspective, or orthographic views

PictorialA three dimensional pictorial is a drawing that shows an object’s three principal planes, much as they would be captured by a cameraSometimes they are called Technical Illustrations

Cavalier ObliqueFront view true sizeReceding Axis Angle (Normally 30°, 45° or 60°) is VariableDepth dimension (receding axis) true size

Cabinet ObliqueFront view true sizeReceding Axis Angle (Normally 30°, 45° or 60°) is VariableDepth dimension (receding axis) half size

Side by Side Comparison

Cavalier Oblique Cabinet Oblique

Which is the cube ?

Were you right?

Angles in Oblique

Angles in front view are drawn true sizeOther angles must be located using coordinatesAppearance of angles may be distorted

Circles in Oblique

Drawn true size in front viewDrawn as ellipses on receding planesLayout using a Rhombus

Cylinders in Oblique

Front and Back surfaces are circular“Sides” are drawn as lines tangent to the front and back

Exercise

Sketch an Oblique of a “classical” tombstone. Add a bullet hole through the stone.

Types of Axonometrics

Orientation of Pictorial Objects

Isometrics

Axes equally separated (120°)H, W, and D measurements are true size along iso. axesAngles must be located by coordinatesCircles appear as ellipses on all surfaces

Isometric Circles & Angles

Isometric Ellipses

Using the Ellipse Template

Drawing Rounded Corners

Construction of CylindersLightly block in the cylinder

Construction of CylindersLightly block in the cylinderSketch the upper and lower ellipses

Construction of CylindersLightly block in the cylinderSketch the upper and lower ellipsesConnect the ellipses with Tangent lines

Construction of CylindersLightly block in the cylinderSketch the upper and lower ellipsesConnect the ellipses with Tangent linesDarken the lines

Practice Exercise

Complete the orthographic views shown and Sketch an isometric of the part.