Capturing the motion of trees

Turns out it's a pretty hard problem. But it does involve quality time outdoors in the wind playing with technology. This is a picture of our set up in a park in Orem, Utah. We've got a laptop next to a weather station in the grass. Some motion capture equipment on a wire running to the tree and a little wind speed measuring device next to the tree.

We made three important discoveries with this set up. First, debugging a technical process in 16 MPH wind is not that easy. Second, we should have brought a little camping table to put our stuff on. Third, our mocap system didn't save our data the way we thought it would save our data and we lost all of our data.

Other than that, it was a good trip.

Directability in weathering simulation

Directability is the ability of a director to exert control over a process which is used to generate an image or shape. Or, said more clearly, directability is artistic control. CG natural phenomena for use in CG film should be directable.

We added some directability to our weathering simulation by allowing the director to edit a curve (really a sequence of line segments) which specify the durability of the rock. The weathered rock takes on the profile of the durability curve.

The resulting process is a lot like the use of curves in specifying plant shapes as found in a paper by Prusinkiewicz called "The use of positional information in the modeling of plants" It's an interesting paper and their images are pretty amazing.

Cavernous weathering

Cavernous weathering is the process by which, well, caverns form in rock. These caverns are also called tafoni. We've been working on a cavernous weathering simulation and have some results. This is a fake canyon which includes some cavernous weathering. The rock shapes were created using our simulation and the image was textured and rendered in Vue. Implemented by Joe Butler.