基於晶格化結構之即時角色皮膚形變技術

Abstract

本論文提出了一個使體網格(Volumetric Mesh)隨著骨骼動畫(Skeleton-driven Animation)即時形變的方法。一般使表面網格(Surface Mesh)隨著骨骼動畫形變的方式為線性混合皮膚形變技術(Linear Blend Skinning)，但是該方法有著數個嚴重的缺點像是需要大量的人工調整。此外，大部分的皮膚形變技術技巧包括線性混合皮膚形變技術都僅著重於主要形變。我們的方法提供一個能夠模擬高、低頻率體效果(Volumetric Effect)例如肌肉隆起與抖動的體形變模型(Deformable Model)，且僅需少量的人工調整。給定一個表面網格，我們將其體素化(Voxelize)來建立一個由方塊組合而成並且包含表面網格的晶格化結構，並套用修改自線性混合皮膚形變技術的晶格平滑皮膚形變技術法(Lattice-based Smooth Skinning)來產生主要形變。接著則套用其他的形變技巧如晶格形狀比對(Lattice Shape Matching)來產生次要形變(Secondary Deformation)的效果。此外，我們的方法可以輕易地實做於圖形處理器上並高效率地執行。

In this paper we present an approach to deform volumetric meshes for skeleton-driven animations in real time. The standard solution of skeleton-driven surface mesh deformation, linear blend skinning, has several critical drawbacks such as heavy requirement of artist intervention. Furthermore, most skinning approaches including linear blend skinning focus on primary deformations. Our approach provides a volumetric deformable model that can simulate the dynamics of both low and high frequency volumetric effects such as muscle bulging and vibrations with little user intervention. Given a surface mesh, we voxelize the mesh to construct a lattice of cubic cells containing the mesh and then we apply lattice-based smooth skinning method based on linear blend skinning to drive the primary deformation. Other deformable techniques such as lattice shape matching are then applied to the volumetric mesh to generate secondary deformations and other effects. Moreover, our approach can be easily implemented on GPUs and executed with high efficiency.