CDT Sectional Views & Auxiliary Views 2 — Questions and Answers
Question 1: What is an offset section?
- A section view displaced to the side of the main drawing for clarity
- A section that uses a stepped cutting plane to pass through multiple features not in the same plane (Correct answer)
- A section taken at an oblique angle rather than parallel to a principal plane
- A section where the hatching is offset from the standard 45° angle
Correct answer: A section that uses a stepped cutting plane to pass through multiple features not in the same plane
An offset section uses a cutting plane that bends or steps to pass through several features lying in different planes, combining them into a single informative section view.
Question 2: What is a revolved section used for?
- To show a rotating mechanism in each of its operating positions
- To show the cross-sectional shape of an elongated feature such as a spoke or rib by rotating it 90° in place (Correct answer)
- To depict the same object from two rotated viewpoints on one sheet
- To indicate that a part may be installed in multiple orientations
Correct answer: To show the cross-sectional shape of an elongated feature such as a spoke or rib by rotating it 90° in place
A revolved section shows the cross-sectional shape of a long feature like a spoke or handle by rotating the cross-section 90° directly onto the view rather than placing it elsewhere on the sheet.
Question 3: How does a removed section differ from a revolved section?
- A removed section shows exterior surfaces while a revolved section shows interior features
- A removed section is placed at a separate location on the drawing rather than rotated in place on the view (Correct answer)
- A removed section uses a different hatching material symbol than a revolved section
- A removed section is always drawn at a larger scale than the parent view
Correct answer: A removed section is placed at a separate location on the drawing rather than rotated in place on the view
While a revolved section is rotated 90° directly on the feature, a removed section is placed at a separate, clearly labeled location on the drawing for better readability.
Question 4: At what angle are standard general-purpose section lines (hatching) typically drawn?
- At 30° to the horizontal
- At 45° to the principal lines of the view outline (Correct answer)
- At 60° to the nearest object line
- Horizontally at 0° for all general materials
Correct answer: At 45° to the principal lines of the view outline
Per ANSI/ASME Y14.3, general section lines are drawn at 45° to the principal lines of the view to clearly distinguish cut material without conflicting with horizontal or vertical object lines.
Question 5: Why are thin features such as ribs and webs typically left unhatched even when the cutting plane passes through them?
- They are too thin for hatching lines to be drawn legibly at standard scale
- Hatching them would falsely suggest a heavy solid cross-section, misrepresenting their structural role (Correct answer)
- ANSI standards exempt all features thinner than 6 mm from sectioning requirements
- They are always shown as hidden lines regardless of whether the cutting plane intersects them
Correct answer: Hatching them would falsely suggest a heavy solid cross-section, misrepresenting their structural role
Leaving ribs and webs unhatched prevents the false impression that they are solid masses, helping readers correctly understand their function as thin stiffening elements.
Question 6: A primary auxiliary view is projected from which view on a drawing?
- Always from the front view, regardless of the inclined surface orientation
- From whichever principal view shows the inclined surface as a true edge (straight line) (Correct answer)
- Always from the top view so that depth dimensions are preserved
- From a secondary auxiliary view in a two-step projection process
Correct answer: From whichever principal view shows the inclined surface as a true edge (straight line)
A primary auxiliary view is projected perpendicular to the inclined surface from the principal view in which that surface appears as a straight edge, ensuring the true shape is captured.
Question 7: What is the purpose of a partial auxiliary view?
- To show only the inclined surface and adjacent features, omitting information already clear in principal views (Correct answer)
- To provide a reduced-scale version of the full auxiliary view to save drawing space
- To show a section cut taken at an angle through the inclined surface only
- To display hidden lines that cannot appear in the primary auxiliary view
Correct answer: To show only the inclined surface and adjacent features, omitting information already clear in principal views
A partial auxiliary view shows only the true-shape portion of the inclined feature, deliberately excluding parts of the projection that duplicate information already shown in the principal views.
CDT Sectional Views & Auxiliary Views 2
What is an offset section?