1. 3 D AutoCAD
30 August 2010

2. Objective 1
Understand the differences between 2D drafting and 3D Modeling 2
Understand the differences between wireframe, surface, and solid models, and know what rendering means 3
Know some of the advantages that 3D models have over 2D drawings, and some practical uses for 3D models 4
Be familiar with some of the 3D capabilities

3. Differences between 3D and 2D
Criteria 3D 2D
1. Viewing Direction
- Look at your object from an angle
- Look straight down on
the drawing plane
2. Object Created
- have depth
- No depth
3. Command related
- 80 AutoCAD commands related primarily to 3D
- however, are also useful in 2D
4. Constructing object
- Yes
- No. Drawing picture from different viewpoints

4. Some Frequently used 3D Terms
Model
3D objects made in AutoCAD called models
2D work referred to as drawing/drafting

5. Some Frequently used 3D Terms
Wireframe Model
Object by its edges only
Wireframe cannot hide object that are behind them
Hole has no meaning in a wireframe model because there is nothing in which to make a hole

6. Some Frequently used 3D Terms
Surface Model
Surface model; solid + empty shell
Surface model often use wireframe models as a frame for their surfaces
Surface model; part wireframe + part surface

7. Some Frequently used 3D Terms
Solid Model
Wireframe, surface model & computer-calculated mass; eg: volume, centre of gravity, mass moment of inertia
Solid models look like wireframe unless a hidden line removal command is in effect

8. Some Frequently used 3D Terms
Rendering
Shaded, realistic-looking picture of a surface solid model is called a rendering
Gray scale rendering
Fully capable of colour rendering

9. Reasons For Using 3D Closer to representing real object than a 2D
Show design more clearly
Good for verifying design as well as for use in presentation and documentation as well.

10. 3D Capabilities of AutoCAD
AutoCAD has complete 3D coordinate system for specifying points and drawing objects anywhere in space
To assist in point input and for working in local area, AutoCAD has a movable user coordinate system
It can set viewpoints from any location in space that can look in any directions

11. 3D Capabilities of AutoCAD
The computer screen can be divided into multiple viewports for simultaneously viewing 3D space from different viewpoints and different direction
AutoCAD has a good assortment of surface entities for making surface models that have a variety of shapes

12. 3D Capabilities of AutoCAD
Solid models of most objects typically manufactured in machine shop can be made within AutoCAD
3D models can be transformed into standard multi-view, dimensioned production drawing
AutoCAD has a built-in renderer with lights and surface materials, capable of making realistic-looking shaded picture from 3D models