Beach Chair (1986)
First CGI water interaction
1) Short film made by Pixar (one of the first their films).
2) It was produced as an animation test by Pixar, but was later shown at the 1986 SIGGRAPH in Dallas, alongside the much better known Luxo Jr.
3) First CGI water animation was in Carla's Island (1981).
4) Directed by Eben Ostby.