论文标题
在具有挑战性的服装中,人类基于神经点的形状建模
Neural Point-based Shape Modeling of Humans in Challenging Clothing
论文作者
论文摘要
像SMPL这样的参数3D主体模型仅代表最小衣服的人,并且很难扩展到衣服,因为它们具有固定的网格拓扑和分辨率。为了解决这些局限性,最近的工作使用隐式表面或点云来建模衣服。虽然不受拓扑的限制,但这种方法仍然很难为偏离身体(例如裙子和连衣裙)的衣服建模。这是因为他们依靠身体来通过将衣服表面放置为参考形状。不幸的是,当衣服远离身体时,这个过程的定义很差。此外,他们使用线性混合剥皮来摆姿势,并将皮肤重量与下面的身体部位绑在一起。相比之下,我们在没有规范化的情况下对局部坐标空间中的衣服变形进行了建模。我们还放松皮肤重量以使多个身体部位影响表面。具体而言,我们用粗糙的阶段扩展了基于点的方法,该方法用学习的姿势独立的“粗大形状”代替了规范化,可以捕获裙子(如裙子)的粗糙表面几何形状。然后,我们使用一个网络来完善该网络,该网络渗透了线性混合的皮肤重量,并从粗糙表示中施加了依赖的位移。该方法适合符合身体并偏离身体的服装。我们通过从示例中学习特定于人的化身,然后展示如何以新的姿势和动作来展示它们的有用性。我们还表明,该方法可以直接从原始扫描中学习缺少数据,从而大大简化了创建逼真的化身的过程。代码可用于研究目的,可在{\ small \ url {https://qianlim.github.io/skirt}}中使用。
Parametric 3D body models like SMPL only represent minimally-clothed people and are hard to extend to clothing because they have a fixed mesh topology and resolution. To address these limitations, recent work uses implicit surfaces or point clouds to model clothed bodies. While not limited by topology, such methods still struggle to model clothing that deviates significantly from the body, such as skirts and dresses. This is because they rely on the body to canonicalize the clothed surface by reposing it to a reference shape. Unfortunately, this process is poorly defined when clothing is far from the body. Additionally, they use linear blend skinning to pose the body and the skinning weights are tied to the underlying body parts. In contrast, we model the clothing deformation in a local coordinate space without canonicalization. We also relax the skinning weights to let multiple body parts influence the surface. Specifically, we extend point-based methods with a coarse stage, that replaces canonicalization with a learned pose-independent "coarse shape" that can capture the rough surface geometry of clothing like skirts. We then refine this using a network that infers the linear blend skinning weights and pose dependent displacements from the coarse representation. The approach works well for garments that both conform to, and deviate from, the body. We demonstrate the usefulness of our approach by learning person-specific avatars from examples and then show how they can be animated in new poses and motions. We also show that the method can learn directly from raw scans with missing data, greatly simplifying the process of creating realistic avatars. Code is available for research purposes at {\small\url{https://qianlim.github.io/SkiRT}}.