We can talk about the greatness of Joe Ranft for a long time, but it is best seen through the lives of those he touched. Ranft worked at Pixar for about 10 years, collaborating with directors John Lasseter, Andrew Stanton, and Pete Docter, among many others. He was clearly loved for his talent and the warmth that he constantly displayed to his fellow employees and friends.
A video tribute to Joe Ranft was included on the Toy Story 2 Blu-ray set and I have embedded it here so we can see just how big of a mark he left at the animation studio. It covers his film career, focusing on his master storytelling skill and his unreal ability to bring others joy and make them laugh. He brought joy to those around him and he continues to bring us all joy to this very day.