Question

The red, blue curve in the figure (shown below) represents __________

(a) welding

(b) joining

(c) fitting

(d) curve of intersection

I got this question by my school teacher while I was bunking the class.

This intriguing question comes from Intersection of Surfaces in portion Development of Surfaces, Isometric Projections, Perspective Projections & Transformation of Projections of Civil Engineering Drawing

Answer 1

Right choice is (d) curve of intersection

For explanation I would say: Whenever two or more solids combine, a definite curve is seen at their intersection. This curve is called the curve of intersection (COI). Lines of intersection are a common feature in engineering applications or products. Figure 1 shows few examples of intersection lines frequently observed in chemical plants, domestic appliances, pipe joints, etc. Curves of intersections are important from the point of view of production of components for engineering applications.