1. AutoCAD 3D Fundamentals
Engineering 22
AutoCAD 3D Fundamentals
Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer

2. Learning Goals Draw Right Hand Coord System
Distinguish between ACAD World CoOrd System (WCS) and User CoOrd Systems (UCS)
In ACAD Create and Save and UCS’s
Use UCS, elev, and thickness to draw “Extruded” Shapes
Use ACAD ViewPorts to Show Orthographic Views from a 3D View

3. AutoCAD CoOrdinate Systems
AutoCAD system maintains a 3D database
World Coordinate System
X,Y as top (plan) view (civil engineering)
Z axis vertical
User Coordinate System (UCS) may be aligned with features (name and save)
Icon shows current coordinate system

4. RIGHT Hand CoOrd Systems
The CoOrd TriAd is Defined by Your RIGHT Hand → Rt-Hand Rule

5. Right-Hand Rule Thumb points in the positive x direction
Index finger points in the positive y direction
Middle finger points in the positive z direction
Used to define positive rotation
Point thumb in the positive direction along the axis which is perpendicular to the plane of rotation
The fingers point in the direction of positive rotation

6. World Coordinate System
The Default 3D Coord
Base System is the World Coordinate System, or WCS
The Orientation of the WCS relative to the Default Screen
We Can find the WCS Icon in the Lower Left

7. WCS Note that the “Z” Axis for the WCS comes OUT of the Screen
Looking “Straight Down” on the Z-axis gives us the familiar “Plan View” 2D Orthographic Drawing System
World Co-ordinate System Set to Origin - Origin is OFF screen
World Co-ordinate System Set to Origin - Icon displayed AT origin

8. View Point
Can Change the “Point of View”, or Viewpoint, for the Object in 3 Ways
WCS View Point

9. Changing ViewPoints
By PullDown Menu

10. The “SW” IsoMetric

11. View Command
view brings up ViewPoint Dialog Box

12. The ViewPoint ToolBar
Can Also Change ViewPoint with The “View” ToolBar
To RETURN to PLAN View in the WCS Use the PullDown Menu

13. Local (User) Coord Systems
The WCS can be MODIFIED to fit the needs of the USER For Drawing in Orientations OTHER than the Plan View
Modify the WCS to a UCS:
Define new origin (with existing axes)
Rotate existing Coordinate System about X, Y, or Z Axis
Define new origin and axes (3-Point option)
NAME and SAVE the UCS

14. User (Local) CoOrd Systems
WCS → (1,4,-3) UCS → (3, 3.5, 0)
UCS
WCS +
(1,4,-0)
(4,1,-3) +
(4,1,0)

15. Making a UCS by Command Ln
Specify an Origin UCS /New
/orthoGraphic (specify the origin relative to the current coordinate system)
Reorient the axes UCS /New
/Zaxis (choose the direction of the Z axis)
/3point (choose the origin and the positive X and Y direction)
/Z (specify the angle of rotation about the Z axis)
Save and Restore the UCS
UCS /Save and UCS /Restore

16. Example → Make a UCS
Make a UCS Called “slant” using the CoOrd from 2-Slides Back
Know origin and pts in WCS space
Start w/ WCS
Use UCS → NEW → 3Point Commands
Invoke UCS/3p to Set Origin to (4,1,0)
Set Points to Define X & Y Axes

17. Result → Make a UCS View from WCS Plan View
Invoke UCS/3p to Set Origin to (4,1,0)
x-Axis INTO Paper

18. Save and Use New UCS Give the New UCS a NAME with the Save command
Change to Plan View for UCS
Command: ucs
Current ucs name: *NO NAME*
Enter an option [New/Move/orthoGraphic/Prev/Restore/Save/Del/Apply/?/World]
<World>: s
Enter name to save current UCS or [?]: slant

19. Plan View in “slant” UCS
Plumbing Fitting Shows Up as Edge View → Not too interesting
Lets Make “twist” UCS by ROTATING the WCS

20. Command History for twist
Command: ucs
Current ucs name: *WORLD*
Enter an option [New/Move/orthoGraphic/Prev/Restore/Save/Del/Apply/?/World]
<World>: n
Specify origin of new UCS or [ZAxis/3point/OBject/Face/View/X/Y/Z] <0,0,0>: x
Specify rotation angle about X axis <90>: 41
Command: UCS
Current ucs name: *NO NAME*
Specify origin of new UCS or [ZAxis/3point/OBject/Face/View/X/Y/Z] <0,0,0>: y
Specify rotation angle about Y axis <90>: 67
Specify origin of new UCS or [ZAxis/3point/OBject/Face/View/X/Y/Z] <0,0,0>: z
Specify rotation angle about Z axis <90>: 13
<World>: s
Enter name to save current UCS or [?]: twist
Use command TEXTSCR to show command history in a separate window

21. Draw Heptagon in twist UCS
Put Dwg-Space into Plan View for twist
Draw a Heptagon in twist-space

22. Drawing in UCS Can ONLY Draw in the CURRENT UCS
WCS Current → PLAN View
To Change UCS Use the Dialog Box Invoked by PullDown
Tools → Named UCS

23. Elev and Thickness Time For Live Demo
300 high
The Elev Command Can Be used to “Extrude” Basic Shapes
Demonstrate by Constructing the Object at Left
Time For
Live Demo

24. EX14-14 → 1 Start new Dwg using acadiso.dwt
Locate and draw the 50x50 “bases” for the “towers”
Change to SE Isometric view
Construct the Tower Using
Elev
Thickness
line

25. EX14-14 → 3 Command: _-view Enter an option [?/Categorize/lAyer
state/Orthographic/Delete/Restore/Save/Ucs/Window]: _seiso Regenerating model.
Command: elev
Specify new default elevation <0.0000>:
Specify new default thickness <0.0000>: 300
Command: l
LINE Specify first point:
Specify next point or [Undo]:
Specify next point or [Close/Undo]:
Specify next point or [Close/Undo]: c
Command:
Command: z
ZOOM
Specify corner of window, enter a scale factor (nX or nXP), or
[All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: e
Regenerating model.

26. EX14-14 → 4 Move UCS to Top Corner by Picking Point w/ Mouse
Draw CrossBar using
Osnap
Elev
Thickness
Enter an option [New/Move/orthoGraphic/Prev/Restore/Save/Del/Apply/?/World]
<World>: n
Specify origin of new UCS or [ZAxis/3point/OBject/Face/View/X/Y/Z] <0,0,0>:

27. EX14-14 → 5 Commands to Construct CrossBar Command: z ZOOM
Specify corner of window, enter a scale factor (nX or nXP), or
[All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: w
Specify first corner: Specify opposite corner:
Command: elev
Specify new default elevation <0.0000>:
Specify new default thickness < >: 50
Command: l
LINE Specify first point:
Specify next point or [Undo]:
Specify next point or [Close/Undo]:
Specify next point or [Close/Undo]: c

28. EX14-14 → 6 Move and Rotate UCS so that the
XY plane Resides on the inside of the 1st tower
Z-axis extend toward 2nd Tower
The Command History (pts Picked)
Command: ucs
Current ucs name: *NO NAME*
Enter an option [New/Move/orthoGraphic/Prev/Restore/Save/Del/Apply/?/World]
<World>: n
Specify origin of new UCS or [ZAxis/3point/OBject/Face/View/X/Y/Z] <0,0,0>: 3p
Specify new origin point <0,0,0>:
Specify point on positive portion of X-axis <1.0000, ,0.0000>:
Specify point on positive-Y portion of the UCS XY plane <0.0000, ,0.0000>:

29. EX14-14 → 7 Draw Connecting Cylinder using
elev → 0
Thickness → 110
Circle → Ø50
EX14-14 → 7
Use xline and offset to Locate Cyl Ctr

30. EX14-14 → 8
Expand Limits, zoom → 1 to fit

31. EX14-14 → 9 Commands to Construct OrthoViewPorts Command: limits
Reset Model space limits:
Specify lower left corner or [ON/OFF] <0.0000,0.0000>:
Specify upper right corner < , >: 210,360
Command: z
ZOOM
Specify corner of window, enter a scale factor (nX or nXP), or
[All/Center/Dynamic/Extents/Previous/Scale/Window/Object] <real time>: 1
Command: -view
Enter an option [?/Categorize/lAyer
state/Orthographic/Delete/Restore/Save/Ucs/Window]: o
Enter an option [Top/Bottom/Front/BAck/Left/Right]<Top>: r
Regenerating model.

32. All Done for Today The AME and Bonus Tol. 3D Orbit Command
Calculating Additional Tolerance Permitted when a Position Tolerance is Modified at MMC.  An additional tolerance, often called Bonus tolerance, is permitted when a position tolerance is modified at maximum material condition (MMC) and the actual mating envelope of the feature has departed from the MMC.  In these illustrations, the part is black and the actual mating envelope is red.

33. Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu
Engr/Math/Physics 25
Appendix 
Time For
Live Demo
Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer

34. Rotate Axis OnScreen

35. EX14-5

36. EX14-5 → zoom → 1

37. EX14-5