Aura Mesh: Motion Retargeting to Preserve the Spatial Relationships between Skinned Characters

Abstract

Applying motion‐capture data to multi‐person interaction between virtual characters is challenging because one needs to preserve the interaction semantics while also satisfying the general requirements of motion retargeting, such as preventing penetration and preserving naturalness. An efficient means of representing interaction semantics is by defining the spatial relationships between the body parts of characters. However, existing methods consider only the character skeleton and thus are not suitable for capturing skin‐level spatial relationships. This paper proposes a novel method for retargeting interaction motions with respect to character skins. Specifically, we introduce the aura mesh, which is a volumetric mesh that surrounds a character's skin. The spatial relationships between two characters are computed from the overlap of the skin mesh of one character and the aura mesh of the other, and then the interaction motion retargeting is achieved by preserving the spatial relationships as much as possible while satisfying other constraints. We show the effectiveness of our method through a number of experiments.

Contact Preserving Shape Transfer For Rigging-Free Motion Retargeting

“…The main contribution of the paper is to explore transferring the shape instead of the pose, assuming that it would better preserve the contextual meaning of the source shape+pose. Whereas other methods [Jin et al 2018;Liu et al 2018] preserve the distances between surfaces, we allow surface interactions (e.g. distances) to change during the transfer because the shape is changing.…”

“…Hence, this paper assumes that transferring the contextual meaning of a source pose to a target character consists in satisfying the distance constraints encoded in this graph, in the target surface mesh. Alternatively, Jin et al [Jin et al 2018] defined the Aura mesh, a volumetric mesh enclosing the body surface with a fixed offset. Spatial relationships are then modeled as the interpenetration of this Aura mesh.…”

“…Thus, changing the morphology of a character while keeping the same pose might result in impossible and/or semantically different poses. Previous works [Ho et al 2010;Jin et al 2018;Liu et al 2018] have solved this problem by deforming the pose to preserve the distances between interacting surfaces or joints. We argue that distances between surfaces are dependent of the character's morphology.…”

“…We argue that our method proposes an alternative to such distance preserving methods [Ho et al 2010;Jin et al 2018;Liu et al 2018], and is a first step in taking into account the correlation between shape and pose in motion retargeting.…”

Surface based motion retargeting by preserving spatial relationship

“…However, their method requires constructing two polyhedral cages for both the source and target shape. Jin et al [2018] propose the aura mesh, which is a volumetric mesh that surrounds a character's skin, to preserve the spatial relationships between two characters. The interaction between two characters is expressed with respect to the collision between the skin mesh of one character and the aura mesh of the other.…”