While I was only on the film briefly, I was given the opportunity to work as an environment modeling artist, working on procedural modeling. While in the modeling department I was tasked with developing a system to generate the interior of the Giant Turtle’s bone structure. The interior of bones tend to be a web like structure, with vertical striations, and thinner horizontal connections. It’s almost in a way evocative of a gluten structure that might form when making sourdough bread.

To briefly describe the method of generating the bone structure, here’s some overly simplistic psuedo-code and some pictures that correspond with each step:

1. Randomly scatter points within the domain you’re trying to generate the bone like structure in.
2. Using the domain as your base, generate a voronoi fracture of said domain, with the randomly scattered points.
3. Convert the voronoi fracture to an edge graph.
4. Grab points near the top and bottom of the edge graph, and compute the shortest paths from the top to the bottom.
5. Pin any edges along the shortest path, and use a laplacian style smoothing operation along all other edges in the edge graph.
6. Mesh the edge graph, making the pinned edges thicker than any non pinned edge. It can help to do some vdb style dilation and erosion here to make things feel more organic.

I recreated the setup for the film, and here’s the project file if you’re interested.