Transcript Sketching Iso and Ellispses

Isometric ellipses
In an isometric
drawing, the object is
viewed at an angle,
which makes circles
appear as ellipses.
Holes
Cylinders
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Sketching a Circle
• Draw a square whose
sides are the diameter
of the circle.
• At the center of each
side define the point
of tangency for the
circle.
• Draw the diagonals of
the square.
• Orient the paper so
you can draw equal
arcs to construct the
circle
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Introduction to Isometric Projection
CUBE
• Isometric means equal measure
• All planes are equally or proportionately shortened and
tilted
• All the major axes (X, Y, Z) are 120 degrees apart
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Making an Isometric
Sketch
• Defining Axis
60o
60o
30o
30o
Isometric Axis
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Ellipses Can be in Any of Three
Planes
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Sketching an Isometric of a
Hollow Pipe
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Step 1 – Creating the Base Box
Diameter
Diameter
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Length
Step 2 – Ellipse on Front Face
- Corner to corner to get center
- Lines to tangent points
Tangent Points
Lines to Tangent
Points
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Step 3 – Ellipse on Front Face
Sketch in Arcs
Tangent Points
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Step 3 – Ellipse on Back Face and
Profile
Repeat for ellipse on rear face
Draw Tangent Lines for Profile
Complete Visible Part of Back
Ellipse
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Step 4 – Ellipse for Hole on Front
Face
Create Box for Hole
Sketch Ellipse
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Isometric of Hollow Pipe
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Summary
• Technical drawings are an effective
communication media
• Projections of various types can be used
• Isometric projections and creating
isometric sketches has been introduced
• Assignments will emphasize simple
isometric sketches
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Review Questions
1. _______ sketches present the object in a single
view, with all three dimensions represented
2. _______ sketches present the object in a series
of projections, each one showing only two of
the objects’ three dimensions
3. Which among the following is NOT an isometric
axes (Hint: Use the Isometric Grid paper for
reference)?
a)
b)
120°
60°
c)
d)
60°
90°
120°
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60°
120°
240°
Tips for Drawing Assignments
• Follow Sketching and Text conventions.
• Title Information is required. Avoid labels
on the sketch.
• Leave the construction lines – MUCH
lighter and thinner than the finished lines
• Include centerlines on isometrics
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Tips for Drawing Assignments
Do not try to shade drawing – this is
not a pencil sketching class.
Use grid paper. Try to sketch along grid
lines. Practice sketching straight lines
and curves on a grid sheet.
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Tips for Pictorial Views
In pictorial views, hidden lines are not shown
unless absolutely required for clarity, such as;
 Non-visible bottom of a blind hole
 Important feature of object not in direct view
In pictorial views, holes or notches without
bottom/end visible should be assumed to go
completely through the object.
Centerlines are to be shown on all isometric
pictorials.
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In Class Assignment

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Use Isometric Sketch Paper (ISP)