## ENG 004 Lecture 4, Oct 9, 2012

### Announcements

- Turn in HW #1 now. Place in stack corresponding to your section.
- Four wait listed students have been added.
- Read beginning of Chapter #5
- Lecture HW #2 will be posted after class.

### Topics

Drawing Types

3D to 2D, 2D to 3D

Diagrams

## Legibility/Communication

## Drawing Types

Projection theory is in Chapter 5

## Projections and Perspective

- One point perspective
- Two point perspective
- Three point perspective
- Parallel Projection (infinite focal point)

## One point perspective

## One point perspective

## Two point perspective

- Most realistic
- Does not preserve scale

## Two point perspective

## Two point perspective

## Parallel Projections

Parallel projection corresponds to a perspective projection with an
infinite focal length (the distance from the image plane to the projection
point)

### Orthographic projection

Parallel project representation of a three dimensional object in two
dimensions

### Axonometric

To measure along axes.

### Multiview Projections

Up to 6 views of an object are projected onto planes perpendicular to the
coordinate axes. The view positions follow one of two schemes: First Angle or
Third Angle

### Pictorial Projections

Image of object from skewed direction to reveal all axes

Isometric, Dimetric, Trimetric

## Axonometric Projections

Type of parallel projection, more specifically a type of orthographic
projection, used to create a pictorial drawing of an object, where the object
is rotated along one or more of its axes relative to the plane of
projection

## Isometric Projections

All three axes are equally foreshortened and angled 120 degrees apart.

Lines are parallel.

## Isometric Projections

## Isometric Limitations

## Isometric Limitations

## Orthographic Axonometric Multiview Projections

### Third Angle Projection

## Orthographic Multiview Projections

## Orthographic Multiview Projections

## Oblique

Projects an image by intersecting parallel rays (projectors) from the
three-dimensional source object with the drawing surface (projection
plane).

θ is typically 45 degrees

x-y scales are the same

z scale is between 0 and 1, usually 1/2

## Oblique

## Drawing Types

## Diagrams

Ideas are captured in a visual format using symbols, words, lines,
etc.

- shows relationships
- show critical issues or functions
- organize concepts
- visual note taking
- free form

### Types

- Graph based: tree, network, flow chart, Venn
- Chart based: histogram, bar char, pie char, function graph, scatter
plot
- Infographics

## Tree diagrams

## Flow chart

Represents an algorithm or process

## Flow chart: Freehand

## Venn diagrams

Show all possible logical relations between a finite collection of
sets

## Engineering Diagrams

- Free body diagrams
- Block diagrams
- Circuit diagrams
- Exploded views
- Hydraulic diagrams
- Sankey diagrams

## Statics: Free Body Diagrams

## Dynamics

## Controls: Block Diagrams

## Materials: Lattice Diagrams

## Fluids: Flow Diagrams

## Fluids: Hydraulic Diagrams

## Thermodynamics: Sankey Diagrams

## Famous Sankey Diagram

## Exploded View

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