The past week has been very hectic, as we have decided that this year, we would concentrate more on doing lots of inhouse work, to please ourselves. The inspiration came from a quote we shared among us, and promised ourselves, that we would do “huge volume of experiments with strict deadlines, which is the only way to bridge the gap between what we think we can do, and what we actually do”.
Rain is one of the most difficult FX to create, because it looks simple, but never is. to make it believeable, a lot many elements have to be taken into account. The real challenge is to create interactions of the water with the scene, elements. The shot we chose to work on, was shot for one of our own productions. You can have a look at it in this video, its the very first shot of the film.
notice that the rain was a simple particle system, camera matched and composited on the shot. it works, but when you deal in HD video or higher, it falls flat. To make the shot sell, we decided that it needed following details.
1. The floor lacked interaction and was visibly wet in patches, but did not look wet enough for a real rain. also, the wetness should have walls reflecting on it.
2. Rain always has three droplet sizes, and they fall at a speed which makes it blur, but still since the water keeps changing its shape due to the velocity and wind, the highlights keep shifting, which gives more like an intermittent shimmering effect.
3. The droplets collide with each other mid air, so the mist is formed, which follows the direction of the wind. If the shot has any cues for the direction of the wind, adding mist makes the shot believable.
4. The droplets fall on the floor, and create splashes. Particle system was used to generate 3 different kinds of splashes.
5. In most old styled houses in the village, there always is some corner where a thick stream of rainwater falls down from the roof. We wanted to use this detail to our advantage, so a metal bucket was placed near the corner, with water falling into it.
7. The water must interact with the actor, the hand rickshaw, and other elements in the shot. We separated them, created a 3D mesh to generate the simulation mesh.
6. During rains, the color saturation is dull, and the ambient light is also reduced drastically. This effect is acheived by color grading the shot as the last step.