Character contact re-positioning under large environment deformation

Character animation based on motion capture provides intrinsically plausible results, but lacks the flexibility of procedural methods. Motion editing methods partially address this limitation by adapting the animation to small deformations of the environment. We extend one such method, the so-called relationship descriptors, to tackle the issue of motion editing under large environment deformations. Large deformations often result in joint limits violation, loss of balance, or collisions. Our method handles these situations by automatically detecting and re-positioning invalidated contacts. The new contact configurations are chosen to preserve the mechanical properties of the original contacts in order to provide plausible support phases. When it is not possible to find an equivalent contact, a procedural animation is generated and blended with the original motion. Thanks to an optimization scheme, the resulting motions are continuous and preserve the style of the reference motions. The method is fully interactive and enables the motion to be adapted on-line even in case of large changes of the environment. We demonstrate our method on several challenging scenarios, proving its immediate application to 3D animation softwares and video games.