Geometric Fracture Modeling in BOLT

Abstract: Modeling the geometry of solid materials cracking and shattering into elaborately shaped pieces is a painstaking task, which is often impractical to tune by hand when a large number of fragments are produced. In Walt Disney’s animated feature film Bolt, cracking and shattering objects were prominent visual elements in a number of action sequences. We designed a system to facilitate the modeling of cracked and shattered objects, enabling the automatic generation of a large number of fragments while retaining the flexibility to artistically control the density and complexity of the crack formation, or even manually controlling the shape of the resulting pieces where necessary. Our method resolves every fragment exactly into a separate triangulated surface mesh, producing pieces that line up perfectly even upon close inspection, and allows straightforward transfer of texture and look properties from the un-fractured model