currently i am working on FX book. here a little sub chapter of it.
To create special effects digital you don’t have to recreate or simulate physically correct like in real world. its not possible anyway. you do not need fancy, custom made solvers. in most cases you just need ordinary standard tools which every 3D package has. First you have to understand, how nature works from visual viewpoint.
the most important thing before you start an effect is, to research: References. you should get as many References as possible. lets use a waterfall / watersplashes as an example. Many fx-artists use videos as visual Reference, but they do not analyze it or do it wrong. most Reference videos give you an idea how your endresult should look like, but you have to remember most of videos are shot in 24 or 30 fps. that means you see motionblurred frames, but you will work opengl viewport of 3d software, with means without motionblur. if recreate you a simulation based on movie, it will ready have motionblured look and the renderengine will add a motionblur at rendertime and this makes your fx streaky (you double the motionblur).
most of the time i go out shot reference video or pictures by myself. l prefer my Nikon v1 Camera. Its cheap (300$), have highend lenses, do superslow motion videos and shot with 1/16000 shuttertime. but any DsLR,with 1/4000 shutter, should do the Trick as well. With shuttertime of 1/4000 or 1/16000, you will get a frame of your reference without motionblur. as you see in the example:
(click on the images and look at the shuttertime on bottom of the images)
if you use “highspeed” images as reference for your scene to create shapes for droplets, you get more realistic look of your effect. your rendersoftware will add correct motionblur.
closeup look at droplets: motionblur (1/160 shutter) and without motionblur (1/8000 shutter)
after you got proper references, you need to read your reference images and extract information to understand visual language. as you can see there are not just bunch blurred particle falling down. there a lot of clumbing “blobb’ing” going on. more details how to read and analyze the reference, i will explain it in part 2