BITS U103 · Narrated walkthrough · Engineering graphics · first vs third angle
First angle or third angle? How to tell, and why it matters
Where the views go comes from one picture: two planes, an object, and a fold. This walkthrough folds the planes in front of you, first with the object in front of them (first angle), then behind them (third angle), and then uses one feature, a step at the front, to prove that last year's Q7 and Q8 were drawn in third angle. Press play, keep the sound on, and answer the two questions it stops to ask.
About five minutes, watch once (⏮ ⏭ replay a scene). It stops twice to ask for your next move. Commit to an answer before it continues. Captions are on; the full transcript is below the player.
Pick one feature you can find on the isometric (a step, a slot, a hole). See which side of each given view it lands on, and draw the missing view the same way round. First angle: the side of a view nearest the front view is the object's back. Third angle: it's the object's front. If the paper prints the projection symbol, that settles it; if not, follow the layout the paper already shows. The worked evidence for Q7 and Q8 is on the past-paper page; practise with the missing-view problems.