Shear Lines, Fronts and Areas of Confluence/Diffluence Mike Davison HPC International Desks.
Lines and Areas
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Lines and Areas • Projections of lines and areas • Meaning of lines and areas in orthographic projections
description
Lines and Areas. Projections of lines and areas Meaning of lines and areas in orthographic projections. Projection of Lines. A. B. A line may be projected in its true length. A line may be fore-shortened. A line may have a point as its projection. Projection of Lines. - PowerPoint PPT Presentation
Transcript of Lines and Areas
Lines and Areas
• Projections of lines and areas• Meaning of lines and areas in
orthographic projections
Projection of Lines
A
B
• A line may have a point as its projection
• A line may be projected in its true length
• A line may be fore-shortened
Projection of Lines
A
BTrue length
Foreshortened
Foreshortened
When will it be seen as a point?
When it is perpendicular to a picture plane.
View
• .• .
If seen as a point in one view, true length in other views!
Reading Areas• A plane surface will always appear in a principal view as a line or an area
Reading Areas• An plane surface that appears as a line in one view is normal to that view. It may or may not appear its true shape in the other views.
Reading Areas• An plane surface that appears as a line in two of the principal views appears as a true shape in the third view.
Reading Areas• A plane surface that appears as an area in two of the principal views cannot be in true shape in any view.
Reading Areas• A plane surface that appears as an area in two of the principal views cannot be in true shape in any view.
Reading Areas• A plane surface that appears as an area in two of the principal views cannot be in true shape in any view.
Reading Areas• Any view that shows a plane surface as area shows it in a like shape
Reading Areas• Any view that shows a plane surface as area shows it in a like shape
Reading Areas
Meaning of Lines in Orthographic Views
• An edge view of a surface
• An intersection of two surfaces
• A surface limit - reversal of direction of a curved surface
Meaning of Lines in Orthographic Views
Intersection
Surface limit
edge view
Edge view
∎
∎∎ ∎ ∎
∎∎ ∎ ∎∎
Another Example
Meaning of Lines in Orthographic Views
Intersection
∎∎
∎
∎∎∎∎∎∎∎∎∎
Surface limit
1. A surface in true shape
2. A foreshortened surface
3. A smoothly curved surface
4. A combination of tangent surfaces
Meaning of Areas in Orthographic Views
Surface in True shape Foreshortened Surface
B B
B
Meaning of Areas in Orthographic Views
Curved Surface
C
C
C
Tangent Surfaces
D
D
D
Meaning of Areas in Orthographic Views
Reading Areas
Oblique surfaces appear as areas of like shape in all views
Adjacent Areas lie in different planes. If two areas were in the same plane, there will not be any boundary between the two.
Reading Areas
