Should I say "I've watched the film in 3D" or "I've watched the film on 3D"?
2 Answers
The former ( in 3D)
Here's a straightforward example from Longman :"a film in 3-D"
3D means three dimensions. Something cannot be seen on those dimensions, but can be seen in them. Had the phrase been '3D t.v.', then it could be seen on a 3D t.v. No mention of that in the question though...