Embedded Implicit Stand‐Ins for Animated Meshes: A Case of Hybrid Modelling

Abstract

Abstract:In this paper we address shape modelling problems, encountered in computer animation and computer games development that are difficult to solve just using polygonal meshes. Our approach is based on a hybrid modelling concept that combines polygonal meshes with implicit surfaces. A hybrid model consists of an animated polygonal mesh and an approximation of this mesh by a convolution surface stand-in that is embedded within it or is attached to it. The motions of both objects are synchronised using a rigging skeleton. This approach is used to model the interaction between an animated mesh object and a viscoelastic substance, normally modelled in implicit form. The adhesive behaviour of the viscous object is modelled using geometric blending operations on the corresponding implicit surfaces. Another application of this approach is the creation of metamorphosing implicit surface parts that are attached to an animated mesh. A prototype implementation of the proposed approach and several examples of modelling and animation with near real-time preview times are presented.

Controlled Metamorphosis Between Skeleton‐Driven Animated Polyhedral Meshes of Arbitrary Topologies

“…With our technique we use the concept of implicit stand‐ins introduced in [KFA*10b]. For each mesh we create its approximation by an implicit surface based on skeleton information.…”

“…However, any other pose of the mesh model can also be used, such as the initial pose of the animation sequence. As was shown in [KFA*10b], the correspondence between the skeleton of the mesh and the skeleton of the implicit surface does not have to be one‐to‐one, as some bones from the mesh rigging‐skeleton can be omitted and some additional segments can be added to the implicit surface skeleton depending on the artist's needs.…”

“…Since successful conversion from meshes to voxels is feasible, a hybrid approach based on the combined use of animated meshes and implicit surfaces looks promising. Such an approach was applied in [KFA*10b], among other things, for the modelling of mesh interactions with viscous substances. The approach presented in that paper involved embedding an implicit convolution surface inside the animated mesh and synchronizing the motions of its skeleton so that the embedded convolution surface stayed inside the polyhedral mesh during the animation process.…”

4D Cubism: Modeling, Animation, and Fabrication of Artistic Shapes

“…This makes FRep essentially a hybrid representation of volumetric objects as not only an object surface, but also its internal points which are uniformly defined by a function. 12…”

Efficient polygonization of tree trunks modeled by convolution surfaces

“…. , p m }, the approach of LS (least squares) in [37,38] is employed for the unknown weights of field contributions from each skeleton Λ = [λ 1 , . .…”