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Visualization and Graphics Introduction
Drafting, Sketching & Dimensioning
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ObjectivesUnderstanding graphics as a communication toolTechnical sketching Freehand Instrument Computer
Projections Orthographic Pictorial
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Visualization
Visualization is often used as a mode of communication between engineersSketches, tables, graphs, computer generated drawings, blueprints are various ways in which engineers communicate via visual mediums
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How Would You Describe This?
In teams of two, describe using only wordsHow effective is this approach?
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Three Basic Types of Technical Drawings
Freehand sketches
Instrument drawings
Computer drawings
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Introduction to Projections
Present 3-D objects with 2-D mediaTwo Basic Categories
Orthographic Pictorial
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Projections: Four Basic Types
Orthographic Projections
Axonometric
Oblique Perspective
Pictorials
Note: Isometric is a special case of Axonometric
Types of Axonometrics
Pictorial DrawingsShows an object like you would see in a photographGive a three dimensional view of a room or structureThree common types Isometric (Axonometric) Oblique Perspective
Pictorial Sketch of Kitchen
Review Questions 1-2
Isometric Drawings
The most common pictorialsConstructed with the two faces 30 degrees above the horizontalThe axes are 120 degrees between each axisLines that are horizontal are drawn at 30 degreesVertical lines remain vertical
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Isometric Projection
• Isometric means equal measure• All planes are equally or proportionately shortened and tilted• All the major axes (X, Y, Z) are 120 degrees apart
CUBE
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Making an Isometric Sketch
• Defining Axis
30o 30o
60o60o
Isometric Axis
Isometric Dimensioning
Dimension lines are parallel to the isometric axesExtension lines are extended in line with these axes
Oblique Drawings
The front view is draw like it would be using orthographic projectionThe front view shows all features with true shape and sizeThe top and side view are then projected back from the front viewViews can be at any angle15, 30 or 45 degrees are common
Oblique Drawing
Oblique Drawings Continued
Useful when the front contains more details and features than the side viewA mental image can be created more quickly than with orthographic aloneTwo types of oblique drawings cavalier cabinet
Review Questions 3-5
Cavalier Oblique
The entire drawing uses the same scaleSometimes creates a distorted appearance
Which is the cube ?
Were you right?
Cavalier Oblique
Front view true sizeReceding Axis Angle (Normally 30°, 45° or 60°) is VariableDepth dimension (receding axis) true size
Cabinet Oblique
Front view true sizeReceding Axis Angle (Normally 30°, 45° or 60°) is VariableDepth dimension (receding axis) half size
Cavalier Oblique Drawing
Cabinet Oblique
Measurements on the receding axes are reduced by halfMore visually realistic representationOften used for drawing cabinets
Cabinet Oblique Drawing
Side by Side Comparison
Cavalier Oblique Cabinet Oblique
Review Questions 6-8
Perspective DrawingsThe most realistic of all pictorial drawingsReceding lines in the drawing “meet” at a vanishing point instead of being parallelEliminates distortion at the back part of pictorial drawingsTwo types parallel (one-point) perspective angular (two point) perspective
Perspective Drawing
Parallel Perspective (One Point)
One face of the object is shown as the front viewLines parallel to the front view remain parallelLines that are perpendicular to the front view converge at a SINGLE VANISHING POINT
Angular Perspective (Two-Point)
Similar to isometric drawingsOne edge of the object is place in frontThe two faces that meet at this edge recede to DIFFERENT VANISHING POINTSAll lines parallel to each face go to the different vanishing points
Angular Perspective Drawing
Types of Perspectives
Horizon Below Object
Exploded Pictorial Drawings
Used to show relative position of parts or construction detailsUsed to clarify assembly sequenceCommon in appliance and cabinetry service manuals
Exploded Pictorial Drawing
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