Professor Popovic comments on the future direction of this work. “What we’re doing now is taking a look at incompressible fluids. We’re looking at water as well as more viscous types of things. The difference between smoke and water is the boundary and what is particularly different is that you can’t compress it like you can compress gas. Water has to preserve volume. That constraint turns out to be very hard to maintain so that volume doesn’t get lost in the process of simulation.”

Creating such high-level controls for computational simulations is challenging. “I think you end up designing different simulations such that you can control them, “ adds Professor Popovic. “In fact, what we’re finding is that we’re designing completely different simulators for water because the current ones, while okay for simulation, are not as powerful as they could be for control.”

Adam Finklestein leads a group project on NPR research. Image of a 3D still life from WYSIWYG NPR courtesy of Professor Adam Finkelstein of Princeton University.

The Trompe L’Oeil Effect: Fighting Three Dimensions with NPR
French art critics in the 19th century coined the term trompe l’oeil for imagery that is so real that it fools the eye into believing that it is in fact a real object that can be touched.

Without a doubt, much of the fanfare for computer animation has come from photorealistic rendering techniques that give people this sensory experience. As Gladstone observes, “The lighting and texturing of things enamors people greatly. Those areas are astounding and only keep getting more polished all the time. That’s the strongest point.”

But a photorealistic effect is not always desired. Professor Canemaker comments, “In CG there is a tendency toward realism. It’s easy to go more real with things instead of styling it and making it more [organic]… You have to work really hard against a trompe l’oeil effect.”

With NPR, animators can combine the best of 3D, as in South Park, and traditional animation, as seen in A Charlie Brown Christmas. South Park © Comedy Central; A Charlie Brown Christmas courtesy of ABC / United Features Syndicate.

Non-photorealistic rendering research (NPR) offers a world of possibilities to those who wish to combine traditional techniques with the underlying technology of 3D computer animation. Audiences love Comedy Central’s South Park. Everyone adores the Peanuts television specials of yesteryear. And they appreciate the unique visual styles that each offers.