Pictorials in AutoCADPictorials in AutoCAD

Class 8.2 : Using AutoCAD to Create Pictorial Drawings

Readiness Assessment Test 8.2.1

Individually take 3 minutes and respond to the following question:

What dimensions are contained on each of the principal projection planes?

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

Sketch pictorials of an object (either oblique or isometric) given orthographic views of the object

Use AutoCAD to generate Isometric Drawings of objects given the orthographic views of the object.

TypesTypes

Obliques– Cavalier– Cabinet

Axonometrics– Isometrics– Others

Perspectives

Cavalier Oblique

Front view true size Receding Axis Angle

(Normally 30°, 45° or 60°) is Variable

Depth dimension (receding axis) true size

Cabinet Oblique

Front view true size Receding Axis Angle

(Normally 30°, 45° or 60°) is Variable

Depth dimension (receding axis) half size

General Oblique

Front view true size Receding Axis Angle

(Normally 30°, 45° or 60°) is Variable

Depth dimension (receding axis) between half and full size

Angles in Oblique

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

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

Circles in Oblique

Drawn true size in front view Drawn as ellipses on receding planes Layout using a Rhombus

Today’s AutoCAD commands

Drawing setup– Drawing Aids

Display control– ZOOM

General Concepts– Keyboard Coordinates

Editing and inquiry– MOVE– COPY– TRIM

Object Snap– ENDPoint– TANgent– NEArest

Drawing Obliques in AutoCAD

Initially you should make a rough sketch of the object 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

Example

Example

Construction of an oblique

Draw the front view using normal AutoCAD commands and techniques

Construction of an oblique Use the COPY command to

replicate the front view to depict the depth

Command: COPYESelect objects: [Other corner:[ 11 found

Select objects:E<Base point or displacement>/Multiple: mEBase point: [Second point of displacement: @.8<40ESecond point of displacement: @1.8<40ESecond point of displacement:E

Construction of an oblique

ERASE the portions of the depth profiles which will not be seen.Command: eraseESelect objects:[Select objects:[…

Select objects: [Select objects: E

Construction of an oblique

Add receding lines using OSNAP and the LINE command.Command: lineEFrom Point: endpE of[To Point: endpE of[To Point:E…

Construction of an oblique

TRIM and ERASE the remaining lines which would not be visible.

Command: TRIMESelect cutting edges: (Projmode = UCS,

Edgemode = No extend)

Select objects: [1 found

Select objects:E<Select object to Trim>/Project/Edge/Undo:[<Select object to trim>/Project/Edge/Undo:E

Exercise 8.2.1

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

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 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 TRIM or ERASE any portions which are not visible

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

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: ellipseEArc/Center/Isocircle/<Axis endpoint 1>: iECenter of circle:[<Circle radius>/Diameter:[

Pair Exercise

Draw an Isometric pictorial of the object shown on the next slide using AutoCAD.

The grid is a .2” grid Use template E38c.dwt Erase the “Robot Foot” Include centerlines at the discretion of your

instructor

Isometric Example

Think-Pair-Share

In the next 1 minute as an Individual if I only answer one question . . . specifically what don’t

you understand about pictorials [at least 3 things] Now take 2 minutes to merge your list with the person sitting next to you AND

add 1 new item to the list In the next 5 minutes share the results with the other half of your team, delete

questions that you can answer for each other, AND prioritize the remaining questions your list

Paired Homework