The dream of customizable virtual 3D foliage is alive at Disney

Devin Coldewey

Oh, to work at Disney, to have a hand in creating those lusciously detailed 3D worlds, every character lovingly rendered, every animal sidekick unique and hilarious, every tree... filled with leaves. Designed and placed individually. In movies that take place in immense forests. There has to be a better way. Well, what if you could just 3D scan some leaves and then tweak them to your liking?

Okay, I doubt every leaf in "Brave" and "Moana" was placed individually, but you better believe making realistic foliage isn't as easy as copy and paste. So anything that makes that particular job easier is almost certainly welcome to the animators, set designers, and others who want make these environments sing.

To the rescue comes "Editable Parametric Dense Foliage from 3D Capture," a paper presented by Disney Research's Gaurav Chaurasia and Paul Beardsley at the International Conference on Computer Vision. It's quite cool.

It works like this: you take a depth-aware image of a patch of foliage, and the researchers' algorithm goes to work identifying individual leaves from the resulting point cloud. it then fits them with elegantly defined Bézier curves that capture the shape of the leaf, from its silhouette to the gentle rise away from the central axis and the beaklike tip (if applicable).

Several examples of how small changes in control point locations produces major changes in the leaf shape.

These curves are extremely efficient ways to store information, and can also be tweaked very easily. By adjusting the control points through which the curves travel, the shape of a leaf, or of every leaf in a tree or forest, can be adjusted in a moment with no need to calculate a whole new mesh.

As the researchers note in the conclusion, "Our goal is not just 3D reconstruction of the widest gamut of leaves. We seek to address artist requirements, which necessitate lightweight editable representation and automatic reconstruction."

Being able to accurately replicate a given bush or tree is also critical to a sense of place; a particular overgrown wall, dense hedge, or unusual shrub might catch an artist or location scout's eye, but merely snapping a picture doesn't always capture the essence of a thing.

This tool doesn't capture the whole scene perfectly, of course, but it can capture that form of orderly chaos so often seen in nature yet so difficult to reproduce artistically. You wouldn't put these directly into a movie, but I'm guessing they sure would help recreate the space:

The primary limitation of the tool is that it only creates single-lobed leaves — so don't expect the next Pixar movie to be set in Canada or anywhere else maples are common.