2. Section 3 Descriptive Geometry
Chapter 12
Auxiliary Views
Section 3 Descriptive Geometry

3. Objectives
List the basic types of auxiliary views and explain the purpose of each type.
Describe the common applications of auxiliary views.
Explain the projection procedures for creating auxiliary views.
Draw primary and secondary auxiliary views using manual and CAD methods.
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4. Auxiliary View Typically used for objects with inclined features.
Common in sheet metal and packaging applications.
True shape and size shown by auxiliary projections.
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5. Projection Applications for Auxiliary Views
True length of a line
Point view of a line
Edge view of a plane
True size of a plane
True angle between planes
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6. Types of Auxiliary Views
Primary auxiliary view
Secondary auxiliary view
Successive auxiliary view
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7. Primary Auxiliary Views
Projected from principal views.
Reference plane numbered to identify type of projection.
Line of sight perpendicular to reference plane.
Depth measurements transferred with tools in manual drafting.
Drawing and editing commands and tracking used in CAD.
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8. Types of Primary Auxiliary Projections
Frontal
Horizontal
Profile
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9. Frontal Auxiliary Projection
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10. Horizontal Auxiliary Projection
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11. Profile Auxiliary Projection
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12. Locating a Point in an Auxiliary View
Projection made perpendicular to reference plane.
Depth taken from top view.
Two points projected similarly to locate a true length line.
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13. Construct a True Length Line in an Auxiliary View
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14. Construct a True Length Line in an Auxiliary View
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15. Determining Slope Auxiliary projection made when line is oblique.
Angle measured from reference plane.
True angles between lines and other principal planes located similarly.
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16. Using the Point Method to Develop an Inclined Surface
Project points to an auxiliary view.
Transfer depth measurements to establish true size surface.
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17. Determining the True Angle between Two Planes
Locate point view of true length line of intersection (Line AB) in auxiliary view.
Project remaining points.
Measure dihedral angle in auxiliary view.
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18. Project Circular Features in Auxiliary Views
Draw principal views and mark divisions.
Project points to inclined surface.
Project points to auxiliary view.
Use irregular curve or ellipse template to complete feature.
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19. Project Circular Features in Auxiliary Views
Draw principal views and divide top view.
Draw construction lines to front view.
Offset lines to create auxiliary view.
Draw ellipse by specifying major and minor axes.
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20. Construct a Principal View Using an Auxiliary View
Construct view where inclined surface is an edge (profile view).
Construct auxiliary view.
Project points back from auxiliary to create front view.
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21. Secondary Auxiliary Views
Projected from primary auxiliary view and one principal view.
Typically used for oblique surfaces.
View must be oriented as viewed in line of sight.
Reference plane constructed perpendicular to line of sight.
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22. Draw a Secondary Auxiliary View
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23. Draw a Secondary Auxiliary View
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24. Draw a Point View of a Line in a Secondary Auxiliary View
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25. Draw a Point View of a Line in a Secondary Auxiliary View
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26. Determine the True Angle between Two Planes
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27. Determine the True Size and Shape of an Oblique Plane
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28. Review Questions
1. What type of auxiliary view is projected from an orthographic view?
Primary
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29. Review Questions
2. An auxiliary view projected from a horizontal view is known as a(n) _____ auxiliary projection.
horizontal
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30. Review Questions
3. The true angle between two planes is called the _____ angle.
dihedral
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31. Review Questions
4. Which of the following must be determined using a secondary auxiliary view?
A. The true length of a line.
B. The point view of a line.
C. The slope of a line.
D. The true size of an oblique surface.
D. The true size of an oblique surface.
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