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Pictorials with AutoCAD

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Pictorials with AutoCAD Class 8.2 : Using AutoCAD to Create Pictorial Drawings Learning Objectives Use AutoCAD to draw an oblique of an object given orthographic ... – PowerPoint PPT presentation

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Title: Pictorials with AutoCAD


1
Pictorials with AutoCAD
Thursday, October 21st 2004
  • Class 8.2 Using AutoCAD to Create Pictorial
    Drawings

2
Learning Objectives
  • Use AutoCAD to draw an oblique of an object given
    orthographic views of the object
  • Select the best orientation of an object in
    pictorial
  • Define what makes a drawing a cavalier oblique,
    cabinet oblique, general oblique, isometric,
    axonometric, perspective, or orthographic views
  • Use AutoCAD to generate Isometric Drawings of
    objects given the orthographic views of the
    object.

3
Types
  • Obliques
  • Cavalier
  • Cabinet
  • General
  • Axonometrics
  • Isometrics
  • Dimetric, Trimetric
  • Perspectives
  • 1,2,or 3 points

4
Cavalier Oblique
  • Front view true size
  • Receding Axis Angle (Normally 30, 45
  • or 60) is Variable
  • Depth dimension (receding axis) true size

5
Cabinet Oblique
  • Front view true size
  • Receding Axis Angle (Normally 30, 45 or 60) is
    Variable
  • Depth dimension (receding axis) half size

6
General Oblique
  • Front view true size
  • Receding Axis Angle (Normally 30, 45 or 60) is
    Variable
  • Depth dimension (receding axis) between half
    (D/2) and full size (D)

7
Angles in Oblique
  • Angles in front view are drawn true size
  • Other angles must be located using coordinates
  • Appearance of angles may be distorted

8
Obliques
  • Obliques are theoretical drawings. In reality,
    you can not actually view an object as an Oblique
  • Thin parts look very good as Obliques
  • Parts with angular features on multiple planes
    are difficult to draw as Obliques

9
Circles in Oblique
  • Drawn true size in front view
  • Drawn as ellipses on receding planes
  • Layout using a Rhombus

10
Todays AutoCAD commands
  • Drawing setup
  • Drawing Aids
  • Display control
  • ZOOM
  • General Concepts
  • Keyboard Coordinates
  • Editing and inquiry
  • MOVE
  • COPY
  • TRIM
  • Review polar coordinates
  • used with copy and move
  • Example _at_1.2lt45
  • Object Snap
  • ENDPoint
  • TANgent
  • NEArest

11
Display Control
  • ZOOM -- scales the screen view to an area of the
    drawing surface
  • Window will zoom down to a window
  • All will zoom out to show the larger of the
    drawn entities or limits
  • Realtime allows you to shrink or enlarge the
    display in real time.
  • PAN -- moves around on the drawing surface

12
Formats of Keyboard Coordinates
  • Either absolute or relative
  • Absolute -- references origin of drawing (0,0)
  • Relative -- references previously selected point
  • Absolute is the default
  • Precede relative coordinates with an _at_ sign
  • _at_10,20 or _at_ 10lt45
  • Direct Distance
  • Enter a distance in the direction of the cursor
    and return

13
Grips
  • Grips serve two purposes
  • Basic editing of properties
  • Modification of size/location
  • Grips are the small hollow squares which appear
    when you select an object
  • If you click on a hollow square grip, it will
    become active and you can drag the grip to a new
    location. The actual effect of this will vary
    depending on what object and which grip you
    select.

14
Modifying Properties via Grips
  • Once an object is selected and the grips are
    visible, you can change the Layer, Linetype,
    Color, and LineWeight by using the properties
    toolbar at the top of the screen.
  • Anytime you have an object activated with grips,
    the properties toolbar modify the object
    properties, not the drawing settings.

15
Drawing Obliques in AutoCAD
  • Always make a rough pencil sketch of the object
    first to get an idea of what your drawing should
    look like.
  • Draw the front view as a flat orthographic view
  • Use the COPY command along with keyboard
    coordinates to place the front view along the
    receding axis to represent all frontal surfaces
    in the object
  • Connect the copies with lines representing the
    depth of the object. Remember to use OSNAP to
    assist in this process
  • Use ERASE and TRIM as appropriate to remove
    unwanted lines/arcs

16
Example
17
Example
18
Construction of an oblique
  • Draw the front view using normal AutoCAD commands
    and techniques

19
Construction of an oblique
  • Use the COPY command to replicate the front view
    to depict the depth
  • Command COPYE
  • Select objects Other corner 11 found
  • Select objectsE
  • ltBase point or displacementgt/Multiple mE
  • Base point
  • Second point of displacement _at_.8lt40E
  • Second point of displacement _at_1.8lt40E
  • Second point of displacementE

20
Construction of an oblique
  • ERASE the portions of the depth profiles which
    will not be seen.
  • Command eraseE
  • Select objects
  • Select objects
  • Select objects
  • Select objects E

21
Construction of an oblique
  • Add receding lines using OSNAP and the LINE
    command.
  • Command lineE
  • From Point endpE of
  • To Point endpE of
  • To PointE

22
Construction of an oblique
  • TRIM and ERASE the remaining lines which would
    not be visible.
  • Command TRIME
  • Select cutting edges (Projmode UCS, Edgemode
    No extend)
  • Select objects 1 found
  • Select objectsE
  • ltSelect object to Trimgt/Project/Edge/Undo
  • ltSelect object to trimgt/Project/Edge/UndoE

23
Exercise 8.2.1 Cavalier Oblique.
Use Template English1.dwt with a receding axis of
30º
24
Isometrics
  • Axes equally separated (120)
  • H, W, and D measurements are true size along iso.
    axes
  • Angles must be located by coordinates
  • Circles appear as ellipses on all surfaces

25
Drawing Isometrics in AutoCAD
  • Initially you should do a rough sketch of the
    object by hand to get an idea of what your
    drawing should look like
  • Switch the crosshairs to isometric mode (snap,
    style, iso)
  • Draw the object using the LINE and ELLIPSE
    commands
  • Use F5 to toggle the current isometric plane
  • Use OTRHO and OSNAP to assist you in the drawing
  • Copy face planes along isometric axes and connect
    corners similar to oblique method shown earlier
  • TRIM or ERASE any portions which are not visible

26
Using isometric snap
  • If the crosshairs are not set in isometric mode,
    use the Drafting Settings dialog box.
  • Right click on snap button and choose settings

27
Drawing Ellipses
  • In isometrics, circular features which lie on the
    principal planes are shown as ellipses
  • These MUST be drawn using the ELLIPSE command
    with the Isocircle option

Command ellipse ENTER Arc/Center/Isocircle/ltAxi
s endpoint 1gt I ENTER Center of circle
ENTER ltCircle radiusgt/Diameter ENTER
28
Individual Exercise
  • Draw an Isometric pictorial of the object shown
    on the next slide using AutoCAD.
  • The grid is a .2 grid
  • Use template English1.dwt

29
Isometric Example
30
Individual Assignment
  • 41 BC Cabinet oblique
  • 43 BC Cavalier oblique
  • 48 CD isometric
  • 49 CD isometric
  • Due Thursday 28 October 2004
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