Line of intersection
In this detailed video, I show you two distinct methods for accurately finding the line of intersection between two given planes, a fundamental concept in descriptive geometry. I start with the more robust but time-consuming auxiliary view method [03:58], which requires generating an edge view of one plane to clearly identify the two piercing points that define the line of intersection, and I show how to project these points back into the original views. As a more efficient alternative, I demonstrate the two-view method [00:46], which relies on projecting the apparent intersections of the planes' edges to quickly locate the piercing points, noting that this method is faster but requires some careful trial and error. Regardless of the method, I finish by explaining how to use apparent intersections to determine the visibility of the planes and line of intersection in the original views, ensuring the final drawing correctly identifies all hidden parts [08:08].
Video Chapters
[00:01] Introduction: Finding the Line of Intersection
[00:46] The Two-View Method (Trial and Error for Piercing Points)
[03:08] Projecting Piercing Points Back to the Front View
[03:34] The Line of Intersection Found by the Two-View Method
[03:58] The Auxiliary View Method (Finding an Edge View)
[04:06] Finding a True Length Line to Create the Edge View
[05:17] Projecting the Second Plane into the Auxiliary View
[06:17] Locating the Piercing Points in the Auxiliary View
[07:11] Comparing Results of the Two Methods
[08:08] Determining Visibility in the Two-View Method
[10:17] Determining Visibility in the Auxiliary View Method