How The ‘Jurassic Park’ Dinosaurs Switched From Stop Motion To CGI

Steven Spielberg’s Jurassic Park, along with other early-to-mid-Nineties films like Terminator 2: Judgment Day and Toy Story, were all part of a breakthrough era in CGI filmmaking. What many people may not realize, however, is that the decision to use computer-animated dinosaurs in Jurassic Park wasn’t made until the film was well into production.

The Academy of Motion Picture Arts & Sciences has released a nine-minute short film called Moments That Changed The Movies: Jurassic Park that talks about the fateful decision to switch from stop motion and animatronics to computer animation for some of the film’s key dinosaur scenes.

I enjoyed watching this doc for a couple reasons. First, it’s always startling to be reminded how young computer animation and visual effects are as art forms; Jurassic Park came out just 21 years ago. Second, it illustrates that big changes in cinematic art are rarely initiated by movie execs or the money people, but begin with the filmmakers and artists themselves. The use of computer animation animation in Jurassic Park was an idea instigated by a group of renegades at ILM, who had initially been hired to add motion blur to the stop motion animation that was being created by Phil Tippett. Many of the principals responsible for the CGI dinosaurs are interviewed in the film including Steve “Spaz” Williams, Stefen Fangmeier, Mark Dippé, and Dennis Muren.

To Spaz Williams from the video:

You had to be arrogant about it because had we failed, that would have been the end. There was no room for failure at this point. I love the term, “You will never…” If I listened to “You will never…” T-Rex wouldn’t have been built.

If you want to see more rare behind-the-scenes footage, Williams has posted additional clips on his Vimeo account, like this T-Rex Bone walk and T-Rex run.


  • martin

    fantastic little doc

  • L_Ron_Backfromthegrave

    Wow, good find. Seeing the comparison between the stop-motion and the CGI that was used makes me question my bias against computer graphics. It might just be that one medium is more appropriate than the other in different situations. I certainly don’t think that CGI should be ruling the market like it is now, animatronics and stop-motion have pretty much become a novelty.

    • jonhanson

      It’s definitely a good reminder of why CGI is everywhere. People take it’s power for granted.

      That said I like that they included the part about how there were still plenty of practical effects. CGI can produce some really realistic imagery but that doesn’t mean that just because you spend millions on CG that it’s going to look better than practical effects.

      I also wonder what stop-motion SFX shots would look like if Laika did them. They talk about fluid motion and Laika has pretty much mastered that in the realm of stop motion.

    • Tim

      You are judging the stop motion animatics to finished CGI shots, which is not a fair comparison. You might want to check out Phil’s work on Dragonslayer which was released in 1981 to see what he could do with his go-motion process.

  • Ryoku240

    As early as Jurassic Parks CGi was it still looks terrific imo. The dinosaurs have structure and weight to them, qualities that’re all too often not apparent in even modern CGi, just compare Jurrasic Parks dinos to any of the CGi in the Star Wars prequels.

    • KW

      Even still watching that film I forget that parts of it are CG. I think its a government cover-up and real live dinosaurs were used.

  • normalized

    Thanks for sharing.
    Ii was always wondering how they did texturing those models made of nurbs with not UV layout whatsoever. But I see in the video they were painting directly on the model? was that alias studio paint? If so, could they finish the texturing in 3d or they had to go to a 2d program for that ?and how to know to manage that when it’s all nurbs patches as it seems?

    • Rick Dolishny

      Pretty sure Alias Wavefront. They did have a crude texture painting app built in. I believe you created the texture map and set the properties first (planer, cylindrical, etc) then worked within that constraint. With careful use of alpha channels you could patch it up without terrible seams.

      I’m still astonished with the level of weight the CGI had. This is something that’s seems lost with modern CGI sometimes.

  • Chris

    I wonder how the next film-Jurassic World-will use practical and CG. One of the problems I think with Joe Johnston’s JP3 is that he didn’t really have a handle on the FX as well as Spielberg did.

  • Rick Dolishny

    I never get tired of hearing this story. There’s one clip that’s missing, it’s a Trex breaking through the trees. I guess that was a later test.

  • Steven Bowser

    I like that they balanced using practical effects with CGI effects. Though you could say that it was only because of limited technology, I think it really does help to make the story more tangible, not only for the audience, but for the actors playing the scene. You can see the real reactions of those kids when the T-Rex crashes down on top of the car because those kids were truly looking at something real.
    I think practical effects and CGI effects should both be used very carefully like they were used in this film.

  • Baze

    Steve “Spaz” Williams was invited to give a talk at the 1993 Puppeteers of America Festival in San Francisco. I recall the audience getting very uncomfortable with the realization animatronics and puppetry were about to get phased out of movies for the foreseeable future.