Interpenetration & Development of Surfaces is one of 9 topics in the Grade 12 Engineering Graphics and Design CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. What is the curve of interpenetration?
The actual line along which the surfaces of two joined solids intersect where one genuinely passes through the other
A type of hidden line used only in isometric drawings
The boundary of a title block
A line used to represent a cutting plane
Answer: The actual line along which the surfaces of two joined solids intersect where one genuinely passes through the other — The curve of interpenetration is the actual line along which the surfaces of two solids intersect, where one genuinely passes through (or into) the body of the other.
Easy
2. Which angles does CAPS Grade 12 require for the joining angle between two interpenetrating solids or tubes?
30, 45, 60 or 90 degrees
Only 90 degrees
Only 45 degrees
Any angle between 1 and 360 degrees
Answer: 30, 45, 60 or 90 degrees — CAPS Grade 12 requires constructing the curve of interpenetration where two solids or tubes/pipes are joined at either 30, 45, 60 or 90 degrees.
Medium
3. Name the constraint on the two solids' axes required by CAPS Grade 12 interpenetration content: they must meet in what kind of common plane?
Answer: in-line — CAPS Grade 12 requires the axes of the two solids or tubes/pipes to meet in a common plane, i.e. in-line only, rather than passing each other at a fixed offset distance.
