There is no general rule for this. You have to know the conventional gerund and noun usages for the word in question. com/dictionary/american/viewing ).
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Anonymousviewing instead of viewThe addition of -ing makes it an activity. A view is like a photo. No motion. You can take a photo of a view.
CalifJimThe addition of -ing makes it an activity.In this example maybe, but in case you meant it as a general rule (I'm not sure you did), I doubt that it works reliably. For example, a run is an activity, while a building is not an activity. As I say, I think you have to know the individual meanings.
GPYIn this exampleYes, and the principle might work for a few others, but certainly not in every case.
CalifJimYes, and the principle might work for a few others, but certainly not in every case.Oh, OK, I may have misunderstood what you were suggesting.
Anonymous "Viewing" has got that dynamic notion whereas "view" is static.Yes, but remember here it is "a viewing", not "viewing". This makes a difference.