A lot of times you will not do the fire in 3D, but you just in compositing by adding fire from one of your thousand movie libraries. The problem of course is th

A lot of times you will not do the fire in 3D, but you just in compositing by adding fire from one of your thousand movie libraries. The problem of course is that you can do that and it might even look good if you match the angle, but you will have a hard time lighting the scene probably, and faking all reflections in. As someone who worked as a camera person I want to emphasize another aspect: Shooting the real thing (fire) is itself not without its challenges. You really need to match light levels well or else you won't even notice fire in the picture. Fire doesn't always burn in visually pleasing ways, and especially outside wind can make or break how it will look.