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GE 121 – Engineering Design - 2009

Engineering DesignGE121

Isometric and Orthographic Sketching

Lecture 3A

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GE 121 – Engineering Design - 2009

Engineering Drawing vs. Sketching

Engineering DrawingsUsed as output of the design process to

communicate the final design for productionPrecise lines and arcs, detailed, and almost

always to scaleEngineering Sketching

Used at conceptual stage of designFreehand, general shapes and sizes, often

just ballpark dimensions, not to a precise scale, but rather simply relative proportions

We will be primarily sketching

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GE 121 – Engineering Design - 2009

Unfolding the ‘Glass Box’

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GE 121 – Engineering Design - 2009

Layout of ViewsStandard Top Front & Right Side

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GE 121 – Engineering Design - 2009

Sketching - Oblique Representation

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GE 121 – Engineering Design - 2009

Sketching - Isometric Representation

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GE 121 – Engineering Design - 2009

Isometric to Orthographic

Orthographic Views are used extensively in engineering

Often, they must be produced from a 3D object or possibly an existing Isometric drawing or sketch

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GE 121 – Engineering Design - 2009

Isometric to OrthographicHints for Orthographic Sketching

• Identify the major features and overall dimensions• Use clean, crisp strokes• Do not use straightedges or scales when sketching• Start by drawing bounding boxes and a miter line, using

construction lines• Align the views• Use light construction lines to locate vertices and edges• Only measure dimensions along primary axes• Map inclined and oblique faces between all three views• Follow the precedence of lines• Doublecheck to make sure there are no missing hidden

or center lines• Darken all visible, hidden and center lines

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GE 121 – Engineering Design - 2009

Iso to Ortho

Block in the 3 views using overall width, height and depth

Front View first, then project height and width using construction lines

Make sure depth is the same on Top and Right Views

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GE 121 – Engineering Design - 2009

Iso to Ortho

Lightly block in major features in each view

Place circles in views where they look round

Begin darkening major features

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GE 121 – Engineering Design - 2009

Iso to Ortho

Construction lines can be used to project location or size of one feature to another view

A miter line can be used to project Depth dimensions

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GE 121 – Engineering Design - 2009

Iso to Ortho

Finish adding all final lines

Be sure to add all hidden and center lines

Darken all final lines

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GE 121 – Engineering Design - 2009

Iso to Ortho

Completed Sketch with construction lines erased

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GE 121 – Engineering Design - 2009

Orthographic to IsometricOrthographic

drawings are common in engineering. Visualizing or creating the Isometric View is a critical engineering skill

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GE 121 – Engineering Design - 2009

Orthographic to Isometric• Hints for Isometric Sketching

• Identify major features and overall dimensions• Use clean, crisp strokes• Do not use straightedges or scales when sketching• Start by drawing a bounding box, using construction lines• Only measure dimensions along the primary axes• Do not directly transfer angles from a multiview to a

pictorial• Use light construction lines to locate vertices and edges• Sketch faces roughly in this order:

1. Normal faces on the perimeter of the bounding box2. Normal faces in the interior of the bounding box3. Inclined faces4. Oblique faces

• Darken all object lines

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GE 121 – Engineering Design - 2009

Ortho to Iso

Set up Isometric Axis using 1 vertical line and 2 lines at 30 degrees from horizontal

Estimate the overall width height and depth of the object, and sketch the edges of a block that would completely enclose the object

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GE 121 – Engineering Design - 2009

Ortho to Iso

Sketch the outline of the front face using lines parallel and equal in length to the two previous height and width edges

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GE 121 – Engineering Design - 2009

Ortho to Iso

Sketch the outlines of the top and side faces using the same basic procedure as used for the front face

Begin sketching start/end points of major features

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GE 121 – Engineering Design - 2009

Ortho to Iso

Begin darkening major features as they are developed

Locate start/end points of additional and smaller features

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GE 121 – Engineering Design - 2009

Ortho to Iso

Locate and sketch start/end points for non-isometric lines such as the angled surface

Sketch and darken the non-isometric features

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GE 121 – Engineering Design - 2009

Ortho to Iso

Completed Isometric Sketch with construction lines erased

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GE 121 – Engineering Design - 2009

Activity

Sketch a closed cell phone in Isometric View, and then in the 3 Standard Orthographic Views (Front, Top and Right Side)

If you complete early, attempt the same with the phone in the open position

Reference Images on the following slide for those without a cell phone to sketch

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GE 121 – Engineering Design - 2009

Reference Images