It was produced in a style that's very similar to traditional cel animation on the Computer Animation Production System (CAPS), developed by The Walt Disney Company in collaboration with Pixar in the late 1980s.
ɪt wʌz pɹədˈuːst ɪn ɐ stˈaɪl ðæts vˈɛɹi sˈɪmɪlɚ tə tɹɐdˈɪʃənəl sˈɛl ˌænɪmˈeɪʃən ɔnðə kəmpjˈuːɾɚɹ ˌænɪmˈeɪʃən pɹədˈʌkʃən sˈɪstəm kˈæps, dɪvˈɛləpt baɪ ðə wˈɔlt dˈɪzni kˈʌmpəni ɪn kəlˌæbɚɹˈeɪʃən wɪð pˈɪksɑːɹ ɪnðə lˈeɪt nˈaɪntiːnhˈʌndɹɪd ˈeɪɾi z.