Chapter 13

Orthographic Sketching

Describing an Angle Bracket

Orthographic ProjectionOrthographic drawings represent three dimensional objects in three separate views arranged in a standard manner.

Orthographic ViewsYou can adequately describe most objects with three orthographic views. Front Top Right

Converting to Orthographic

Orthographic Views –Line Types

Line Types

Visible LineHidden LineCenter LineDimension LineConstruction Line

Line Types

Sketching Techniques

Engineering Drawing SkillsLetteringLine TypesOrthographic ViewsPatience

See the example drawings in the notes.

Engineering Drawing RulesAlways use a Pencil.Make all lettering the same size.Use Engineering or Drafting Paper.

Orthographic ViewsYou can adequately describe most objects with three orthographic views. Front Top Right

Sketching techniquesUse very light construction lines“Box in” the rough outline of the objectDarken only the lines you wish to keepClean up the edges and rough spots

Orthographic Projection

2 Dimensional projections on Orthogonal planesShow lines based on change of plane or change of materialUse multiple linetypes Visible Hidden Center

Describing an Angle Bracket

A relatively simple objectPictorial view may be difficult

Glass Box concept

Envision the object surrounded in a glass boxProject the views out onto the pieces of glassEach pane shows a 2D projection of the object

Completed Orthographics

Projection Planes

The three panes of glass represent the principal orthographic planes Horizontal Frontal ProfileEach plane illustrates two of the principal dimensions: Height, Width, and Depth

Class Exercise

As a team you have 3 minutes to discuss the following:What dimensions are contained on each of the principal projection planes?

The Glass Box Approach

Orthographic Projection

Opening the Box

Final Views

Six Orthographic Views

Laying Out All Six Views

Three Primary Views

View SelectionIf the object has an obvious top, then it must be the top viewMinimize the number of hidden linesUse the most descriptive view as the front viewConserve space by choosing the depth to be the smallest dimension

Precedence of Lines

Construction of Views

Must align orthographic viewsWidth appears in Top and FrontHeight appears in Front and SideDepth appears in Side and TopHeight and width project directlyDepth must be projected via a 45° angle

Steps in Creating the Three-View Sketch

Step 1 - Lightly Block Three Views

Use very light lines

for drawing in

the constructio

n lines

Step 2 - Lightly Block Major Features

Step 3 - Add Features, Use Miter Line

Steps in Creating the Three-View SketchStep 4 - Add Final Lines

Steps in Creating the Three-View SketchCompleted Sketch

Think-Pair-ShareIn the next 1 minute as an Individual if you could ask a question . . . specifically what don’t you understand about today’s topic what would it be. [at least 3 items should be listed]Now take 2 minutes to merge your list with the person sitting next to you AND add 1 new item to the listIn the next 5 minutes share the results with the other half of your team, delete questions that you can answer for each other, AND prioritize the remaining questions your list

Team Exercise

Complete three orthographic views of the object shown on the next slide.Include visible, hidden, and center lines where appropriate.Use the grid paper in the back of your book or your engineering sketch pad.You will be given 7 minutes.

Object for exercise