Realistic smell effect I'm about to model a piece of cheese, and I would like to give it some kind of smell effect as it's known from cartoons when a cheese is too old, or if someone with smelly feet takes off the shoes... Well, guess you know what I mean...

Now I want to make that kind of effect in blender. Of cause, it's going to be in 3D, and I hope it's possible to make it look a little more realistic than the cartoons. Also, I would like the "stink" to be half green, half transparent so that it is visible, and you know exactly what it is, but still not so green, that it looks more unrealistic than it's necessary. 

I only need this effect for pictures, so it doesn't need to have an animation effect to it.
Here is what I came up with (Since it wont be animated I decided not to use smoke sim).




I used grease pencil D+Mouse click to draw the smoke.
Convert stroke to curves then in the curve menu I had the fill set to HALF and extruded until it looked good.  
Then convert it to a mesh ALT+C.
I brought it into sculpt mode with a smooth brush and fixed all the wrinkles and odd looking things. Then used the blob brush to add thicker bulges where I thought they looked good. 
Duplicated the smoke and changed how it looked with more sculpting and scaling. 
The material added is just a simple diffuse (Principled BSDF) mixed with a transparent shader using a noise texture. I added a 2nd mix shader and transparent node to bring the overall transparency down. 


Hope this helps.