SAN FRANCISCO — Pat Hanrahan was a young biophysics student at the University of Wisconsin-Madison in the 1980s when he decided to give up his work with microscopic insects and join a small group of computer scientists in their quest to make a movie.

The group was led by Ed Catmull, a computer graphics pioneer who had become the chief technology officer at a new company called Pixar. The movie was “Toy Story,” the landmark animated feature released in fall of 1995.

On Wednesday, the Association for Computing Machinery, the world’s largest society of computing professionals, said Dr. Hanrahan and Dr. Catmull would receive this year’s Turing Award for their work on three-dimensional computer graphics. Often called the Nobel Prize of computing, the Turing Award comes with a $1 million prize, which will be split by the two pioneers of what is often called C.G.I., or computer-generated imagery.

Their work changed not only animated movies but Hollywood special effects, video games, and virtual reality.