Synchronized Multi-Character Motion Editing 多角色同步动画编辑 （一）介绍 翻译

Manmyung Kim Kyunglyul Hyun Jongmin Kim Jehee Lee

Seoul National University

Figure 1:78 characters carry boxes in relay. We interactively manipulated the synchronized multi-character motion to shape a spiral.

Abstract

The ability to interactively edit human motion data is essential for character animation. We present a novel motion editing technique that allows the user to manipulate synchronized multiple character motions interactively. Our Laplacian motion editing method formulates（构想） the interaction among multiple characters as a collection of linear constraints and enforces the constraints, while the user directly manipulates the motion of characters in both spatial and temporal domains. Various types of manipulation handles are provided to specify absolute/relative spatial location, direction, time, duration, and synchronization of multiple characters.  The capability of non-sequential discrete editing is incorporated into our motion editing interfaces, so continuous and discrete editing is performed simultaneously and seamlessly. We demonstrate that the synchronized multiple character motions are synthesized and manipulated at interactive rates using spatiotemporal constraints.

CR Categories: I.3.7 [Three-Dimensional Graphics and Realism]: Animation—Virtual reality

Keywords: Character Animation, Interactive Motion Editing, Human Motion, Motion Capture, Multi-Character Interaction

对于角色动画以交互方式编辑的人体motion数据的能力是必不可少的。我们提出一种新的motion编辑技术 来允许用户互动的操作 多人的交互角色motions。我们的Laplacian motion编辑方法 指定将多个角色之间的交互当作一个线性约束和强制约束的集合，同时用户直接操作角色的motion 在时间和空间域上。提供了各种类型的操作句柄来指定多角色的绝对/相对空间位置、 方向、 时间、持续时间和同步时间。非顺序 离散编辑的能力 纳入了我们的编辑界面，因此 连续的和离散的编辑都可以表现的无缝和同事的。我们 实现了 以交互的速度上在时间和空间的约束下实现 多个角色motions的合成和操作

CR 类别︰ I.3.7 [三维图形和现实主义]: 动画 — — 虚拟现实

关键词︰ 角色动画、 交互式运动编辑、 人物运动，运动捕捉，多人物互动

1.Introduction

The ability to interactively edit human motion data is a vital tool for character animation. The common goal of motion editing is to make a desired change to existing motion data while preserving the essential quality and features of the original motion as much as possible. Interactive editing techniques typically allow the user to manipulate motion data by specifying pinning constraints and dragging its moving trajectory directly.

1.介绍

以交互方式编辑的人体motion数据的能力是角色动画的重要工具。motion编辑的共同目标是同时保留的基本元素和特点的同时尽可能多地对现有的运动数据进行所需的更改。交互式编辑技术通常允许用户通过指定的固定约束和直接拖动其运动轨迹来操作运动数据。

Collaborative and adversarial interaction among multiple characters usually requires synchronization in both space and time. Most existing motion editing techniques allow the motion of each individual character to be manipulated independently. Editing synchronized multi-character motions can be cumbersome if the animator has to maintain interpersonal constraints manually for synchronization. We present a novel interactive motion editing technique that allows the animator to specify the interaction among characters as a collection of linear constraints and manipulate synchronized multiple character motions simultaneously, while maintaining the constraints. Various types of manipulation handles and interpersonal constraints are provided to specify absolute/relative spatial location, direction, temporal duration, and timing of interaction. The user can stretch and squeeze synchronized motion data in both spatial and temporal domains through intuitive, easy-to-use user interfaces.

多个角色之间的协作性和对抗性交互通常需要保持时间和空间上的同步。大部分的动画编辑技术允许对每个单独的角色操作运动。而编辑多角色同步的动画师很麻烦的，动画师不得不通过手动来使角色之间交互的约束。我们提出一种新型的交互式动画编辑方式，允许动画师指定多个角色之间的相互作用为线性的集合 和 在同时操作多个角色的运动同时可以保持角色之间的约束。我们提供了各种类型的操作手柄（manipulation handles）和人际约束（interpersonal constraints）来指定 绝对/相对空间位置，方向，时间和计时的相互作用。用户可以通过直观的、易于使用的用户界面 在空间和时间域上缩放同步的动画数据。

Our motion editing method is based on a one-dimensional version of Laplacian mesh editing [Igarashi et al. 2005; Sorkine et al. 2004]. This method allows a polygonal curve to be deformed in an as-rigid- as-possible manner. We generalize this idea to deal with synchronized motion paths. To do so, we discuss how to incorporate spatial/temporal constraints into the Laplacian formulation and how to cope with degenerate cases. We employ this path editing algorithm for both spatial path editing and interactive time warping, which requires smooth time-warp curve editing. Therefore, the spatial and temporal aspects of motion data can be handled uniformly.

我们的动作编辑方法基于一维版本的拉普拉斯网格编辑 [Igarashi et al. 2005; Sorkine et al. 2004]。此方法允许多边形曲线以尽可能保持刚性（as-rigid-as-possible）的方式变形。我们总结出这样的思路来处理动作路径的同步。这样，我们讨论如何将 空间/时间约束（temporal constraints）纳入拉普拉斯构想（Laplacian formulation）以及如何应对退化情况。我们利用这个路径编辑算法来为空间路径和互动时间的变形，这就要求平稳的时间变形（time-warp）曲线编辑。因此运动数据的空间和时间方面可以统一处理

The Laplacian editing method makes smooth, continuous changes to the original motion by warping its moving trajectory. The underlying structure of the motion remains intact for mild stretching, squashing, and bending. However, discrete, structural transformations of motion (for example, adding or removing walking steps) should be made to accommodate large edits in the motion path. Such discrete motion editing can be implemented by segmenting motion data into short clips and splicing them in a novel order [Lee et al. 2002; Kovar et al. 2002]. Our system incorporates non-sequential discrete editing capabilities seamlessly into motion editing interfaces, so discrete changes can ensue as fluidly as continuous path editing during interactive manipulation. Discrete optimization of a motion path is notorious for its exponential computation complexity with respect to the number of potential discrete transformations. General discrete optimization using a collection of rich connected motions is impractical for interactive applications. Fortunately, interactive editing is inherently incremental and thus no sudden jump is permitted in manipulation. This gradual change assumption allows us to achieve interactive performance by taking an efficient, incremental strategy.

拉普拉斯编辑方法可以通过变形其运动轨迹 对原始动画 添加平滑、连续的变化。这个motion的技术结构 为 mild 伸展，挤压和弯曲 保持完好。然而，离散、结构转换的motion（例如，添加或删除走的步数）应制作成能 容纳大量的编辑在motion路径上。这种离散motion 编辑可以执行 通过分割分割motion数据为较短的clips并且在一种新的order[Lee et al. 2002; Kovar et al. 2002]下编辑它。我们的系统无缝（non-sequential）地在motion编辑界面中加入（incorporates） 了非顺序离散编辑功能，因此在交互式操作期间 离散变化 可以像编辑连续路径一样流畅。motion路径的离散优化 众所周知其 指数级的计算复杂度 及潜在的离散转换的数量。一般的离散优化是使用丰富的连接动作的集合 这是不切实际的交互式应用程序。幸运的是，交互式编辑是固有增量，因此在操作中没有突然的跳跃。这种渐变变化假设允许我们以一种高效的增量策略实现交互式表现。

The continuous and discrete editing capabilities of our system are demonstrated with examples that require precise spatiotemporal control of multiple characters interacting with each other and environment objects. Our specific contributions are threefold.

A unified formulation that can deal with spatial, temporal, and inter-personal manipulation

A framework that seamlessly combines continuous and discrete motion editing

An user interface that allows for intuitive manipulation of synchronized multi-character motion

我们系统的连续和离散的编辑能力，并用以下实例论证 需要 对多个角色彼此交互和周围物体交互 进行时空上的精确控制。我们具体的贡献有三个方面。

• 可以处理空间、 时间temporal、人和人之间 操纵 的统一的构想

• 一个框架，无缝地结合连续和离散motion编辑

• 一个用户界面，允许直观操作的同步多角色motion