1. GMED UNIT 1
Pictorial Drawings

2. Pictorial Drawings

3. 15-1 Pictorial Drawings Types of pictorial drawings
Types of axonometric drawings
Isometric drawings
PhotoDisk

4. Types of pictorial drawings:
Axonometric projection

5. Types of pictorial drawings:
Oblique projection

6. Types of pictorial drawings:
Perspective

7. Axonometric projection
Definition:
Axonometric projection
A projected view in which the lines of sight are perpendicular to the plane of projection, but in which the three faces of a rectangular object are all inclined to the plane of projection.
PhotoDisk

8. Types of axonometric projection:
Isometric
The three principal faces and axes are equally inclined to the plane of projection
Dimetric
Two of the principal faces and axes are equally inclined to the plane of projection
Trimetric
All three faces and axes make different angles with the plane of projection

9. SHAPE DESCRIPTION
The AXONOMETRIC projection is a three dimensional representation in which the lines of sight are perpendicular to the plane of projection.
ISOMETRIC
DIMETRIC
TRIMETRIC

10. Isometric drawings The object is revolved 45 to the horizontal.
The object is tipped up or down 3516’.
Lines are drawn to true length.

11. True measurements are made along three major axes, which are:
ISOMETRIC PROJECTION
True measurements are made along three major axes, which are:
VERTICAL
30 degrees up to the LEFT
30°
30°
30 degrees up to the RIGHT
30°
Drawing object to actual measurement

12. ISOMETRIC PROJECTION
The basic procedure used in drawing isometrics is to use an isometric grid.
Next, draw all lines along the three major axes.

13. ISOMETRIC PROJECTION
When sketching, use isometric grid paper as a guide.

14. 15-2 Curved Surfaces in Isometric
Circles and arcs in isometric drawings
Irregular curves
PhotoDisk

15. A circle drawn in isometric
has the shape of an ellipse on any of the three faces.

16. ?
Quick Quiz
Isometric, dimetric, and trimetric are types of what kind of pictorial drawing?
Axonometric projection

17. Common Features in Isometric
15-3
Common Features in Isometric
Isometric sectioning
Drawing conventions: Fillets, rounds, and threads
PhotoDisk

18. Sections in isometric The section is taken on an isometric plane.
In full section, construction lines represent the part cut away.

19. 15-4 Oblique Projection Types of oblique projection
Drawing objects in oblique projection
Inclined surfaces

20. Oblique projection drawings
The object is placed with one face parallel to the frontal plane.
The other two faces are placed on oblique (receding) planes at a convenient angle.
The three axes are vertical, horizontal, and receding.

21. Types of oblique projection
Cavalier oblique
All lines a drawn in their true length.
Cabinet oblique
Lines on the receding axis are shortened by one-half.

22. 15-5 Common Features in Oblique
Circles and arcs
Sections in oblique
Drawing conventions
Lawrence Lawry

23. Circles in oblique projection
When possible, the face having circles or arcs should be selected for the front face.

24. Methods for drawing circles or arcs on an oblique face:
The offset measurement method
The four-center method
In CAD: Use the ellipse command, specifying degree of exposure.

25. Quick Quiz ? What are the two types of oblique projection?
Cavalier and cabinet

26. One-Point, Perspective
15-6 Parallel, or
One-Point, Perspective
Perspective projection
Types of perspective drawings
Perspective drawing and sketching
PhotoDisk

27. Definitions: Picture plane: The plane of projection
Station point: The position of the observer’s eye

28. Definitions: Horizon: An imaginary horizontal line taken at eye level
Vanishing point: A point on the horizon where receding lines converge

29. Types of perspective drawings
Parallel
One vanishing point

30. Types of perspective drawings
Angular
Two vanishing points

31. Types of perspective drawings
Oblique
Three vanishing points

32. There are three types of PERSPECTIVE projections:
SHAPE DESCRIPTION
There are three types of PERSPECTIVE projections:
1. PARALLEL VP
Vanishes to one point

33. There are three types of PERSPECTIVE projections:
SHAPE DESCRIPTION
There are three types of PERSPECTIVE projections:
2. ANGULAR
Vanishes to one point
Vanishes to one point

34. There are three types of PERSPECTIVE projections:
SHAPE DESCRIPTION
There are three types of PERSPECTIVE projections:
3. OBLIQUE
Vanishes to one point
Vanishes to one point
Vanishes to one point

35. 15-7 Angular, or Two-Point, Perspective
Angular perspective drawing and sketching
Angular perspective in CAD

36. Grids for angular perspective sketching
Exterior
Interior
Bird’s-eye view
Worm’s-eye view

37. 15-8 Solid Modeling Types of solid modeling Image generation
Data extraction
Jonnie Miles

38. Types of solid modeling:
Wire-frame models
Surface models
Solid models

39. Types of solid models
Constructive Solid Geometry (CSG) ( to come) Combines shapes using Boolean operations (union, subtraction, and intersection)
Boundary Representation (BREP)
Joins surfaces using extrusion or by revolution

40. ?
Quick Quiz
What kind of perspective drawing has two vanishing points?
Angular perspective