PDI/DreamWorks - Sprout

  • Scott Peterson
    Lead Effects Animator
    PDI/DreamWorks


    In an effort to broaden his knowledge of animation, Scott Peterson created the animated short film entitled "Sprout." With this film, he was able to tackle such tasks as storyboarding, character rigging, animating, set-dressing, and directing that were previously unfamiliar.

    While creating Sprout, Peterson also served as a Lead Effects Animator on PDI/DreamWorks’ hit animated feature, SHREK. He developed several foliage systems for the film and also animated several large-scale effects.

    Prior to his contributions on SHREK, Peterson worked as an assistant animator on PDI/DreamWorks’ first animated feature film, ANTZ. He started his computer graphics career as a technical director intern at Rhythm and Hues Studios.

    Peterson earned his Bachelor of Science degree in Computer Science from California Polytechnic State University, San Luis Obispo in 1997. While at Cal Poly, he won first place in the engineering category of the California Student Research Competition for his senior project entitled "Modeling Organic Forms Using Soft Primitives."

    3D Festival: Can you tell us, what your responsibilities were in the creation of Sprout?

    Scott Peterson: I was responsible for direction, story, animation, and effects. For the first half of production, I worked primarily by myself. Among the many people that taught me about the various aspects of production, I chose two key supervisors: Simon Smith and David Rader. They helped me through the story process, layout, and character animation. By the time I completed milestones for each of these, I had done enough work to produce two shorts. I used the trashcan liberally. I switched to a supervisor role for the lighting and surfacing aspects of Sprout. The general enthusiasm for shorts here is so high that recruiting lighters and texture artists was easy.

    3D Festival: Can you in your best words describe what "Sprouts" are?

    Scott Peterson: A "Sprout" is a highly adaptive creature developing inside of its egg. It is very clever and inquisitive even before it is born. In fact, the birth process for a Sprout begins when it figures out a way to solve the puzzle of "How do I get out of my egg?".

  • 3D Festival: Where did the story of Sprout originate from?

    Scott Peterson: Sprout was originally called "Ozzy the Osmotic." Ozzy looked exactly like Sprout, except that he ate food through his feet. The original story involved Ozzy completing three contrived tasks served up on a series of pedestals. After completion, his dome-shaped growth cell, which was a metaphor for an egg, opened up to a huge world. His mother didn't know how to carry him off, so she grew a pocket on her back to hold him in. The story was miserably difficult to understand. I couldn't even believe or understand it myself, so I threw it away. Sprout's new tasks involved only one simple initiative: stay connected to the umbilical cord. To make the environment more organic, Sprout literally begins inside his egg. In the end, Sprout makes a discovery rather than his mother.

    3D Festival: why was the short 'Sprout' produced?

    Scott Peterson: I created Sprout in order to learn aspects of production that I don't normally work on as an effects animator. I wanted other people who helped me to have the same opportunity.

    3D Festival: The character rig for Sprout was quite impressive, most evident when his legs grew. How was the underlying skeletal rig able to adjust to this change?

    Scott Peterson: Sprout's hip scale propagates down the joint hierarchy of his legs, and terminates at his feet.

    Fortunately, Maya's rotate/plane inverse kinematics solver accounts for scale. I assigned skin weights and reactive muscle bulges for the full size of his legs. When his legs are short, I created a target shape that cancels out most of the muscle and bone definition. Also, expressions nullify the bulges that I set up for the long legs.

    3D Festival: One aspect that immediately caught my attention was the'lively' ambience to the music, can you elaborate on that?

    Scott Peterson: Marco D'Ambrosio at MarcoCo. Studios did a fantastic job interpreting my oral sketch. His credits include most of PDI's recent short films, and the score for Vampire Hunter D: Bloodlust. Like most other aspects of Sprout, I directed him down the wrong path at first. After a week of creating some whimsical percussion-heavy music, I asked him to switch directions. Inside the egg, the music needs to convey a tiny scale using high pitches and a fast, staccato rhythm. It also needs to build up in layers as Sprout's body changes to adapt to his environment. Outside the egg, it needs to sound large and fearful. Marco not only hit these marks, but he also figured out a way to bring the song together as a whole the end of the short. I can't imagine a more talented and patient composer to work with than Marco.


    Click the image above to see Sprout dangling from the umbilical cord

    Click to see Sprout stretching his legs
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  • 3D Festival: The texture work on the main character had a very rubber/latex look to it, how was this accomplished?

    Scott Peterson: The translucent property of the material is a new technique that Juan Buhler developed for PDI. Most of our shading models only take into account light entering and leaving a surface from the same point. Juan's technique, as described in a paper that he co-authored in the SIGGRAPH Proceedings this year entitled "A Rapid Hierarchical Rendering Technique for Translucent Materials," approximates light that bounces around underneath the surface.

    Sprout's skin absorbs and scatters light similar to how soft materials such as latex or frog skin might. Translucency also indicates the scale of objects. A small marble paperweight is highly translucent compared to a large marble statue. Sprout's highly translucent skin indicates his tiny scale.

    3D Festival: For such a simple character, his facial expressions were very communicative, how many facial targets were created for Sprout?

    Scott Peterson: There were three components to Sprout's facial expressions. His eyes could scale, his brow could wrinkle a couple of different ways, and his eyelids could blink and rotate.
    His eyebrows had about six target shapes. The eyelids were not controlled by target shapes because they had to slide tight over the eyeballs such that they looked like they made contact, but not so tight that the eyeball would penetrate through them.

    They also had to rotate in order to mimic what was happening in Sprout's brow. In addition to facial animation, I had a simple deformation lattice that I used to change the shape of Sprout's upper body in order to convey emotion or to exaggerate the forces exerted on his body.

    3D Festival: In the cave scene, there was a burst of water where Sprout drilled through the wall, was this proprietary based fluid dynamics?

    Scott Peterson: I used the same fluid simulation software that we used in Antz and Shrek. The biggest challenge an animator faces here is to render the fluid. I tried something a little bit different for Sprout. I rendered particles into a volume of densities, and filtered that volume using thickening and thinning algorithms. Thickening and thinning smoothes out the blobby artifacts usually associated with surfaces constructed from particles. I rendered the volume as an isosurface. I also projected some of the particles from the simulation back onto the surface, and clustered them into tendril patterns in order to add the foamy texture to the water.

    3D Festival: How long did the production take from concept to finish?

    Scott Peterson: Three years passed from start date to end date. I don't like to admit that it took so long. To account for some of that time, I was working on Shrek as a lead effects animator, and I am the proud father of a fast and clever two-year-old Sprout named Benjamin Peterson now.


    Sprout meets his mom for the first time

    Sprout learns to bungie jump?
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  • 3D Festival: How many artists worked on the short?

    Scott Peterson: There were two texture artists, seven lighters, two other effects animators, one composer, and one sound designer who worked on Sprout. I was very happy that two of the lighters on Sprout are render assistants here, so they took the opportunity to expand their careers through this project.

    3D Festival: Sprout was shown at SIGGRAPH's 2002 Electronic Theatre, but there hasn't been any information regarding the short on PDI/DreamWorks website or on the internet. Any particular reason for this?

    Scott Peterson: We are focused on entering Sprout in film festivals right now. I suppose the latency also reflects the grass roots nature of short filmmaking at PDI/Dreamworks. Management doesn't decide to make shorts here, animators do. I like it that way. I'm just an effects animator who wants to learn more about production.

    3D Festival: We appreciate you taking the time to give us insight on PDI/DreamWorks "Sprout".

    Scott Peterson: Thank you for giving me the opportunity to share some of my experience in making Sprout.

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    Related Links:
    PDI/Dreamworks Offical website

    Special thanks to Amy Krider of PDI/Dreamworks for making this interview possible.

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