DCG Revision - Solids in Contact

Solids in Contact is all about drawing Orthographic Views of tangential solids. The shapes that we need to focus on are Cones, Spheres, Hemispheres, Pyramids and Cylinders. It is important to know the difference between Solids in Contact and Interpenetration of Solids:
  • Solids in Contact - Solids touch each other but do not cut into each other
  • Interpenetration of Solids - Solids cut into/through one another.

It is even more important that you remember that although they are different topics Solids in Contact and Interpenetration of Solids share the same fundamentals. 

Syllabus Learning Outcomes (NCCA, 2006)

What you Need to Know!

Ordinary Level

  • Find a given point on a Cylinder, Cone (generator and horizontal section methods), Sphere and Pyramid in all Orthographic Views.
  • Draw a combination of 2 of a Cone, Sphere, Cylinder, Hemisphere and Pyramid in mutual contact (including Points of Contact).
  • Draw a combination of 3 of a Cone, Sphere, Cylinder, Hemisphere and Pyramid in mutual contact (including Points of Contact).

Higher Level

  • Draw a combination of 2 and 3 of a Cone, Sphere, Cylinder, Hemisphere and Pyramid in mutual contact using Loci (including Points of Contact)
  • Find the traces of Tangent Planes to a Sphere and a Cone individually
  • Find the trace of a Tangent Plane to both a Sphere and Cone

Practice Textbook Questions (Anderson, 2014)

  1. P49 Q8
  2. P49 Q9
  3. P52 Problem 3
  4. P53 Problem 4
  5. P57 Q2
  6. P57 Q3

Past Exam Paper Questions

  1. 2009 A-4
  2. 2011 A-4
  3. 2013 A-2
  4. 2017 A-3

References

NCCA (2006). Leaving Certificate Design and Communication Graphics Syllabus. Dublin: The Stationary Office.
Anderson, D. (2014). Graphics in Design and Communication: One Volume Edition. Dublin: Gill & Macmillan.