Back in the 50's I was taught 3rd angle, 1st angle was referred to as 'American projection, I think that at some stage there was a general change to 1st angle, perhaps to conform with other counytrys.

I still use 3rd angle, seems more logical to me, and use dotted/dashed lines for hidden entities.

I asked my enginneering mananager son what they used and he said 3rd angle, he said that in a previous job 1st angle caused so much hassle with customers and suppliers that they changed to 3rd angle.