Technical Drawing was a core required course for first and second year Engineering students (Electrical, Civil, Mechanical, Electronic) in Commonwealth countries in the 1980s and for decades before.
Descriptive Geometry was a major component of Tech Drawing, everybody in pre CAD digital age (and still, I'd say at least) needed a good grounding in blueprints, schematics, and "constructive drawing" good enough to take measures from during building.
Wow, I've been perusing books on drawing/sketching and scouring videos and blog posts for years, and none of them mentioned "descriptive geometry". Perhaps they did and I just missed it, but seems unlikely given how much I retread materials.
Descriptive Geometry was a major component of Tech Drawing, everybody in pre CAD digital age (and still, I'd say at least) needed a good grounding in blueprints, schematics, and "constructive drawing" good enough to take measures from during building.
https://en.wikipedia.org/wiki/Technical_drawing
https://en.wikipedia.org/wiki/Descriptive_geometry