Any reference to good values for smoke opacity

[stevesideas]

I'm new to using the opacity for the smoke to create fine details. Is there any type of preset or reference set of graphs I can use ?

[Svetlin.Nikolov]

Really depends on the look you are after. Is it the helicopter scene? The opacity graph is most useful for coffee and cigarette-style effects. You could also use it to make the smoke appear very dense and massive or in order to cut away completely some portions of it, but for this kind of scene I doubt that it would be very useful. You could probably add some drag particles like in this scene: https://www.youtube.com/watch?v=XpYJOIVSUx4