Date post: | 17-Dec-2015 |
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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