Transcript Sketching Iso and Ellispses

Fundamentals of Engineering
Isometric Pictorials and Ellipses
GSMST
Objectives
Projections: The Four Basic Types
Creating Isometric sketches
Sketching Ellipses
2
Projections: Four Basic Types
Note:
Isometric is a
special case of
Axonometric
Orthographic
Projections
Axonometric
Pictorials
3
Oblique
Perspective
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
4
Making an Isometric
Sketch
• Defining Axis
60o
60o
30o
30o
Isometric Axis
5
Usage of the Grid Paper
Correct orientation
Incorrect orientation
Note the alignment of the axes
7
Going From Isometric to Rectilinear
8
Object for Practice
9
Making an Isometric
Sketch
•
Axis Convention
Height
Width
Front view
10
Depth
Isometric Axis
Convention
Choose the
longest
dimension to be
the width (or the
depth) for optical
stability
Blocking in the Object
Begin with Front Face
Front Face
Height
Width
11
Blocking in the Object:
Add Side Face
Side Face
Height
Depth
12
Blocking in the Object:
Add Top Face
Top Face
13
Adding Detail Cut Outs –
Part 1
14
Adding Detail Cut Outs –
Part 2
15
Adding Detail Cut Outs –
Part 3
16
Darken Final Lines Part 4
Note:
All visible edges
will be darkened
17
Draw the Isometric
• Use Isometric Grid Paper
• Block is 6 x 3 x 3
18
Isometric View
19
Draw the Isometric
20
Draw The Isometric
21
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
22
Isometric ellipses
In an isometric
drawing, the object is
viewed at an angle,
which makes circles
appear as ellipses.
Holes
Cylinders
23
Ellipses Can be in Any of Three
Planes
24
Sketching an Isometric of a
Hollow Pipe
25
Step 1 – Creating the Base Box
Diameter
Diameter
26
Length
Step 2 – Ellipse on Front Face
- Corner to corner to get center
- Lines to tangent points
Tangent Points
Lines to Tangent
Points
27
Step 3 – Ellipse on Front Face
Sketch in Arcs
Tangent Points
28
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
29
Step 4 – Ellipse for Hole on Front
Face
Create Box for Hole
Sketch Ellipse
30
Isometric of Hollow Pipe
31
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
32
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°
33
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
34
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.
35
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.
36
In Class Assignment

37
Use Isometric Sketch Paper (ISP)