Fast Arbitrary Splitting of Deforming Objects

Denis Steinemann, Miguel Otaduy, Markus Gross

We present a novel algorithm for efficiently splitting deformable solids along arbitrary piecewise linear crack surfaces in cutting and fracture simulations. We propose the use of a meshless discretization of the deformation field, and a novel visibility graph for fast update of shape functions in meshless discretizations. We decompose the splitting operation into a first step where we synthesize crack surfaces as triangle meshes, and a second step where we use the newly synthesized surfaces to update the visibility graph, and thus the meshless discretization of the deformation field. The separation of the splitting operation into two steps, along with our novel visibility graph, enables high flexibility and control over the splitting trajectories, provides fast dynamic update of the meshless discretization, and facilitates an easy implementation, making our algorithm scalable, versatile, and suitable for a large range of applications, from computer animation to interactive medical simulation.

Peeling a virtual apple. As the peeler slices through the apple, the skin deforms and falls off. The apple consists initially of 2121 simulation nodes and 6124 triangles, and it is peeled at 25 fps.

The advantages of our approach can be clearly seen interactive cutting in a surgical simulator. Progressive cuts (i.e. without any lag between tool movement and cutting) can be produced interactively at more than 45 fps. Moreover, because we are not re-meshing a volumetric mesh, the cut corresponds exactly to the path of the tool and the physical simulation stays stable at the same time.

Self-Colliding Jell-O. Spiral cuts induce challenging self-collisions that are handled robustly thanks to our explicit boundary representation.

Smashed Pumpkins. Our algorithm for synthesizing crack surfaces is used for prescoring fracture.

• D. Steinemann, M. A. Otaduy, M. Gross, Fast Arbitrary Splitting of Deforming Objects, Proceedings of the 2006 ACM SIGGRAPH/Eurographics Symposium on Computer Animation (Vienna, Austria, September 2-4, 2006), pp. 63-72
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