I have this projection of two intersecting cones, and I am asked to draw the intersection curve of the two cones on the projection. What is the right way to do it? enter image description here

  • 1
    $\begingroup$ I would first imagine the shape of the intersect, then locate the points of intersection... $\endgroup$
    – Solar Mike
    May 28, 2019 at 16:15
  • $\begingroup$ That is what I am struggling with- locating the points of intersection. I think that there are specific generating lines of the wider cone that intersect with specific generating lines of the narrower cone. I just can't seem to find those specific intersection points. $\endgroup$ May 28, 2019 at 16:19
  • $\begingroup$ Start with the center lines then locate the four extremities on those lines and then continue to draw the dots... $\endgroup$
    – Solar Mike
    May 28, 2019 at 16:21
  • $\begingroup$ I found two intersection points so far- on the top view and the side view- using the two intersection points in the front view(of the center lines). How do I go further with this? $\endgroup$ May 28, 2019 at 16:27
  • $\begingroup$ You don't seem to have grasped the basic idea of why projections are useful. Suppose you take a generating line from the top of the large cone. You can draw the same line on all three projections, and each projective view will tell you something about how it intersects the small cone. Piece that information together and you have the point of intersection. (Actually you don't need all three views - two are enough). $\endgroup$
    – alephzero
    May 28, 2019 at 17:20

1 Answer 1


Have look at this and then see which intersections give you the points for the outline (this is not exact - just lines drawn on a simple graphics package...


enter image description here


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