Automatic shape adjustment at joints for the implicit skinning

Automatic shape adjustment at joints for the implicit skinning

Olivier Hachette, Florian Canezin, Rodolphe Vaillant, Nicolas Mellado, Loic Barthe.
CNRS, IRIT, Université de Toulouse, France.

Elsevier Computer&Graphics (proc. of SMI 2021)

The implicit skinning is a geometric interactive skinning method, for skeleton-based animations, enabling plausible deformations at joints while resolving skin self-collisions. Even though requiring a few user interactions to be adequately parameterized, some efforts have to be spent on the edition of the shapes at joints.

In this research, we introduce a dedicated optimization framework for automatically adjusting the shape of the surfaces generating the deformations at joints when they are rotated during an animation. This approach directly fits in the implicit skinning pipeline and it has no impact on the algorithm performance during animation. Starting from the mesh partition of the mesh representing the animated character, we propose a dedicated hole filling algorithm based on a particle system and a power crust meshing. We then introduce a procedure optimizing the shape of the filled mesh when it rotates at the joint level. This automatically generates plausible skin deformation when joints are rotated without the need of extra user editing.

Overview of our approach. (a) Input mesh and its associated skeleton. (b) Model segmentation with respect to the skinning weights. (c) Mesh parts resulting from the input mesh segmentation. (d) 0.5-iso-surfaces interpolating the mesh parts of the forearm in blue and the hand in yellow. (e) Bulging shape generated at the wrist joint when parts are rotated. (f) Closure of the mesh parts following the 0.5-iso-surfaces and pre-fairing of the extremity shapes. (g) Iterative shape optimization removing the bulge when limbs rotate. (h) Post-fairing generating the final shape for rigging the model. (i) Result of the implicit skinning applied on our optimized shapes at joints.


title = {Automatic shape adjustment at joints for the implicit skinning},
journal = {Computers & Graphics},
year = {2021},
issn = {0097-8493},
doi = {},
url = {},
author = {Olivier Hachette and Florian Canezin and Rodolphe Vaillant and Nicolas Mellado and Loïc Barthe},
keywords = {Shape deformation, Geometric modeling, Skinning},