# pictorial sketching

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Chapter 5

Pictorial Sketching

Objectives

Axonometric& ObliqueProjection

Axonometric Projection

Axonometric ProjectionType of axonometric drawing2. DimetricTwo angles are equal.3. TrimetricNone of angles are equal.1. IsometricAll angles are equal.Axonometric axisAxonometric axisAxonometric axis

Parallel & obliqueto picture planeOblique Projection

Oblique ProjectionOblique drawing angleType of Oblique drawing1) Cavalier2) Cabinet

Isometric Projection& Isometric drawing

Rotate 45about vertical axisTilt forward (35o16)Isometric ProjectionAll edges foreshortenabout 0.8 time.

Isometric DrawingIsometric drawing is a drawing drawn on an isometric axes using full scale.Isometric projection(True projection)Isometric drawing(Full scale)

Positions of Isometric AxesIsometric axes can be arbitrarily positioned to create different views of a single object.RegularisometricReverse axisisometricLong axisisometricView point is lookingdown on the top ofthe object.View point is lookingup on the bottom ofthe object.View point is lookingfrom the right (or left)of the object.

Distance in Isometric DrawingIsometric axesNonisometric lines

Isometric Sketching

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.1. Place the object in the position which its shape and features are clearly seen.Sketch from an actual object

STEPS1. Positioning object.2. Select isometric axis.3. Sketch enclosing box.4. Add details.5. Darken visible lines.Sketch from an actual object

1. Positioning object.2. Select isometric axis.3. Sketch enclosing box.4. Add details.Sketch from an actual objectSTEPS5. Darken visible lines.

1. Interprete the meaning of lines/areas in multiview drawing.2. Locate the lines or surfaces relative to isometric axis. Sketch from multiview drawing

Example 1 : Object has only normal surfacesRegularReverse

Example 2 : Object has inclined surfaces

Example 3 : Object has inclined surfaces

RegularExample 4Reverse

Circle & Arc in Isometric2. Construct an isometric square.3. Sketch arcs that connect the tangent points.Sketching Steps1. Locate the center of an ellipse.

Circle & Arc in Isometric3. 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.Sketching Steps2. Construct an isometric square.1. Locate the center of an ellipse.

Example 5

Irregular Curve in Isometric1. Construct points along the curve in multiview drawing. 2. Locate these points in the isometric view.3. Sketch the connecting lines.Steps

ObliqueSketching

Object Orientation GuidelinesPlace complex features (arc, hole, irregular shapesurface parallel to frontal plane.

Object Orientation GuidelinesThe longest dimension of an object should beparallel to the frontal plane.GOODWORSEGOODWORSE

Object Orientation GuidelinesWhich orientation is better ?

ESTIMATE DEPTHESTIMATE LINESSketch from actual object

Sketch from multiview drawing

Sketch from multiview drawing

Sketch from multiview drawing

ABCDESketch from multiview drawing

ABDECSketch from multiview drawing

ABDECSketch from multiview drawing