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

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

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

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

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

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

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

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

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

10. Today’s AutoCAD commands n Drawing setup – Drawing Aids n Display control – ZOOM n General Concepts – Keyboard Coordinates n Editing and inquiry – MOVE – COPY – TRIM Review polar coordinates used with copy and move: Example: @1.2<45 n Object Snap – ENDPoint – TANgent – NEArest

11. Display Control n 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. n PAN -- moves around on the drawing surface

12. Formats of Keyboard Coordinates n Either absolute or relative – Absolute -- references origin of drawing (0,0) – Relative -- references previously selected point n Absolute is the default n Precede relative coordinates with an @ sign – @10,20 or @ 10<45 n Direct Distance – Enter a distance in the direction of the cursor and return

13. Grips n Grips serve two purposes: – Basic editing of properties – Modification of size/location n Grips are the small hollow squares which appear when you select an object n 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 n 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. n Anytime you have an object activated with grips, the properties toolbar modify the object properties, not the drawing settings.

15. Drawing Obliques in AutoCAD n Always make a rough pencil sketch of the object first to get an idea of what your drawing should look like. n Draw the front view as a flat orthographic view n 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 n Connect the copies with lines representing the depth of the object. Remember to use OSNAP to assist in this process n Use ERASE and TRIM as appropriate to remove unwanted lines/arcs

16. Example

18. Construction of an oblique n Draw the front view using normal AutoCAD commands and techniques

19. Construction of an oblique n Use the COPY command to replicate the front view to depict the depth Command: COPY E Select objects: [ Other corner: [ 11 found Select objects: E /Multiple: m E Base point: [ Second point of displacement: @.8<40 E Second point of displacement: @1.8<40 E Second point of displacement: E

20. Construction of an oblique n ERASE the portions of the depth profiles which will not be seen. Command: erase E Select objects: [ … Select objects: [ Select objects: E

21. Construction of an oblique n Add receding lines using OSNAP and the LINE command. Command: line E From Point: endp E of [ To Point: endp E of [ To Point: E …

22. Construction of an oblique n TRIM and ERASE the remaining lines which would not be visible. Command: TRIM E Select cutting edges: (Projmode = UCS, Edgemode = No extend) Select objects: [ 1 found Select objects: E /Project/Edge/Undo: [ /Project/Edge/Undo: E

23. Exercise 8.2.1: Cavalier Oblique. Use Template English1.dwt with a receding axis of 30º

24. Isometrics n Axes equally separated (120°) n H, W, and D measurements are true size along iso. axes n Angles must be located by coordinates n Circles appear as ellipses on all surfaces

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

26. Using isometric snap n 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 n In isometrics, circular features which lie on the principal planes are shown as ellipses n These MUST be drawn using the ELLIPSE command with the Isocircle option Command: ellipse [ ENTER ] Arc/Center/Isocircle/ : I [ ENTER ] Center of circle: [ ENTER ] /Diameter: [ ENTER ]

28. Individual Exercise; n Draw an Isometric pictorial of the object shown on the next slide using AutoCAD. n The grid is a.2” grid n Use template English1.dwt

29. Isometric Example

30. Individual Assignment n 41 B&C: Cabinet oblique n 43 B&C: Cavalier oblique n 48 C&D: isometric n 49 C&D: isometric n Due: Thursday 28 October 2004