How many frames of animation does it take to make a 3 minute film?

This depends on how smooth you want your animation to look the minimum frame rate is usually 12 frames per second therefore 12fps * 60(seconds per minute) * 3(minutes) = 2160 frames if you want to try different frame rates use the equation f(x) = x * 180 where x = the number of frames per second to find the number for frames you will have to take to complete your video.