Chapter 5: Orthographic Views

Agenda

• 3 Views of an Object• Projection between Views • Hidden lines and precedence• Demonstration• Compound Lines• Oblique Surfaces• Rounded Surfaces• Holes, in slanted surfaces

Visualization

• Ability to look at a 3D object and mentally see the appropriate 2D orthographic views

• Ability to look at a 2D ortho drawing and mentally picture the 3D object

• This class is going to develop that skill

Line Types

Visible LineHidden LineCenter LineDimension LineConstruction Line

Visible

Linetype Precedence

Demonstration

• We’ll tackle our first multi-view drawing• First we’ll set up layers for

– hidden, center, construction, and final lines

• We’ll draw the overall layout• Then we’ll fill in the details• Transfer construction lines into final lines

Layers and Linetypes• Click on Object Properties Tool

– change color, linetype, lineweight by layer– Layer Properties Manager (ObjPrp or Format)

• New, name = hidden, New, name = center• Click on Hidden Layer line, select color and LT

– Load hidden and center if necessary, choose • Can turn a layer on/off (lightbulb), scale linetypes

• Draw on different layers– Switch with Layer control tool– Make Object’s layer current– Select object, switch layer LCT, 2x(esc)

Mod: Cut a Channel

• Cut channel thru bottom of object• Use hidden lines to show channel

• Work on 1st two problems in A4.doc

Demonstration II

• This drawing has a number of slanted surfaces intersecting in ways that need additional care to portray accurately

Oblique Surfaces

• Not shown “true” in any view• Hard to visualize, must rely on projection

Rounded Surfaces

Holes

• Holes viewed head on need center lines • Holes viewed sideways need hidden and

centerlines• Holes into slanted surfaces become ellipses in

some views. Use projection to create bounding rectangle, fill in with ellipse