Section 1 Introduction to Drafting

2. Chapter 4 CAD Commands and Functions Section 1Introduction to Drafting

3. Objectives • List several general categories of commands used in popular CAD programs. • Explain how points and objects are located using a coordinate system. • Explain the use of linear, angular, and leader dimensioning. • Identify and describe drawing aids.

4. Objectives • Discuss the purposes of colors, linetypes, and layers. • Explain layer naming conventions as related to CAD drawings. • Describe 3D drawing. • Explain rendering. • Explain animation.

5. Types of CADCommands • File management • Drawing • Editing • Display control • Dimensioning

6. Command Entry Methods • Pull-down menus • Toolbars • Command line • Tablet

7. File Management Commands • Used to create, save, or open file. • Files may originate from scratch or template. • Drawings should be saved every 10 to 15 minutes.

8. Coordinate Systems • Used to specify point locations for objects. • Cartesian coordinate systemis most common.

9. Cartesian Coordinate System • X axisand Y axisused to locate points. • Points designated as (X,Y). • XY drawing plane sufficient for 2D work.

10. Types of Coordinate Entry • Absolute coordinates • Relative coordinates • Polar coordinates

11. Absolute Coordinates • Measured from origin (0,0). • Most basic way to locate points.

12. Relative Coordinates • Used to locate point from previous point. • Designated with @ symbol.

13. Polar Coordinates • Used to locate points at relative distance and angle. • Designated @distance<angle. • Angles typically measured from 0 horizontal.

14. Three-Dimensional Coordinates • Z axisused to define “vertical” measurement. • Points designated as (X,Y,Z).

15. User Coordinate System (UCS) • Used to establish different origin from world coordinate system. • Commonly used with 3D drawing functions. • Created with UCS command.

16. Line Double Line Point Circle Arc Spline Ellipse Rectangle Polygon Drawing Commands

17. Line Command • Used to draw straight lines. • Two points specified. • Coordinates entered or picked on screen.

18. Double Line Command • Used to create parallel lines. • Allows user to set distance between lines.

19. Point Command • Used to create point objects. • Helpful for construction purposes. • Visibility modes used to change display.

20. Circle Command • Used to create circles based on user input. • Center and radius • Center and diameter • Three points • Two points

21. Arc Command • Used to create arcs based on user input. • Three points • Start, center, end • Start, center, angle • Start, center, chord length • Start, end, radius

22. Spline Command • Provides several ways to create spline. • Picking points along curve. • Converting existing lines into spline.

23. Ellipse Command • Used to create ellipse. • Points specified for major and minor axes.

24. Rectangle Command • Provides several methods for drawing rectangles. • Width and height • Opposite corners

25. Polygon Command • Provides several options to create regular polygon. • Circumscribed • Inscribed • Side length

26. Text Command • Used to create text objects. • Allows text font to be set. • Provides justification and rotation options.

27. Hatch Command • Used to “hatch” areas in section views. • Provides selection of standard material patterns. • Internal areas typically picked for hatching.

28. Erase Undo Move Copy Mirror Rotate Scale Fillet Chamfer Trim Extend Array Editing Commands

29. Mirror Command • Used to “mirror” objects about mirror axis. • Useful for symmetrical features.

30. Fillet Command • Used to create fillet or round. • Creates radial curve between two selected objects.

31. Chamfer Command • Used to chamfer corners. • Operation similar to Fillet command.

32. Array Command • Used to copy objects in rectangular or polar pattern. • Rows, columns, and offset specified for rectangular array. • Number of objects, center point, and angle specified for polar array.

33. Arrays

34. Inquiry Commands • List • Properties • Distance • Area

35. List and Properties Commands • Used to display object data. • Coordinates • Line lengths • Layer assignments • Linetype settings

36. Area Command • Used to make area and perimeter calculations. • Points picked to define enclosed area.

37. Display Control Commands • Zoom • Pan • View • Redraw • Regenerate

38. Zoom Command • Used to enlarge or reduce display of objects. • Does not change actual size of objects. • Allows “real time” zooming and specified magnification factor. • Useful for “zooming in” on object details.

39. Pan Command • Used to move drawing on screen. • Does not “zoom” drawing. • Helpful for large drawings with objects “off” screen.

40. View Command • Used to save current display of drawing. • Allows restoring certain display without zooming or panning.

41. CAD Dimensioning • Provides major advantage over manual drafting. • Permits flexibility for placement of text and dimension elements. • Types of commands relate to dimension method and content.

42. Dimensioning Commands • Linear • Angular • Diameter • Radius • Leader

43. Drawing Aids • Grid • Snap • Ortho

44. Grid • Used to show display gridon screen. • Composed of configuration of dots. • Provides visual cue for drawing size and spacing.

45. Snap • Permits alignment of cursor with specific points on screen. • Useful for “connecting” to endpoints, intersections, and centers. • Provides critical tool for ensuring accuracy of point locations.

46. Types of Snap • Grid snap • Object snap

47. Common Object Snaps • Endpoint • Center • Midpoint • Perpendicular • Tangent • Intersection

48. Ortho • Forces lines to be drawn horizontally or vertically. • Useful when lines must be drawn “square.” • Must be deactivated to draw inclined lines.

49. Layers • Similar to overlays in manual drafting. • Each object has assigned layer. • Used to control visibility of drawing content. • Usage typically regulated by company or industry standards. • Same naming conventions should be followed by everyone working on project.

50. Display Colors • Typically assigned to layers to identify content. • Useful for distinguishing dimensions and text from object lines. • Usage often dictated by layer standards.