A Rigging‐Skinning Scheme to Control Fluid Simulation

Abstract

Inspired by skeletal animation, a novel rigging‐skinning flow control scheme is proposed to animate fluids intuitively and efficiently. The new animation pipeline creates fluid animation via two steps: fluid rigging and fluid skinning. The fluid rig is defined by a point cloud with rigid‐body movement and incompressible deformation, whose time series can be intuitively specified by a rigid body motion and a constrained free‐form deformation, respectively. The fluid skin generates plausible fluid flows by virtually fluidizing the point‐cloud fluid rig with adjustable zero‐ and first‐order flow features and at fixed computational cost. Fluid rigging allows the animator to conveniently specify the desired low‐frequency flow motion through intuitive manipulations of a point cloud, while fluid skinning truthfully and efficiently converts the motion specified on the fluid rig into plausible flows of the animation fluid, with adjustable fine‐scale effects. Besides being intuitive, the rigging‐skinning scheme for fluid animation is robust and highly efficient, avoiding completely iterative trials or time‐consuming nonlinear optimization. It is also versatile, supporting both particle‐ and grid‐ based fluid solvers. A series of examples including liquid, gas and mixed scenes are presented to demonstrate the performance of the new animation pipeline.

A Survey on SPH Methods in Computer Graphics

“…Although there is high‐demand from industry, work on artist control still seems to be niche and so far only a few SPH‐specific papers have been published, e.g. , [ZYWL15,LCY*19,SPDM20].…”

Efficient and high precision target‐driven fluid simulation based on spatial geometry features

“…Cornelis et al 13 realized that the fluid could be converted between the target object and the fluid, enabling a more efficient and simplified solver. Lu et al 2 also proposed to drive the movement of fluid more intuitively by means of rigging movement and fluid skin. Schoentgen et al 3 proposed that different driving templates should be prefabricated to make it easier for artists to achieve the desired effect.…”

“…However, it could only generate an approximate surface of a simple toy object, but cannot handle complex models with a large ratio of surface‐to‐volume ratio. Lu et al 2 proposed to drive the movement of fluid more intuitively by rigging‐skinning mechanism. This method is effective, but the flow characteristics tend to be lost due to the dense sampling of control particles and the excessive control constraints.…”

A Dynamic Mixture Model for Non‐equilibrium Multiphase Fluids

“…Fluid control is a trending topic that is partially related to this work. Again, only the most relevant works are briefly summarised here, while we refer to recent works such as [LCY*19] for a more detailed overview on this topic. The previous works on fluid control mainly focus on single phase fluids, while multiphase fluids are potentially more challenging to apply control techniques.…”

“…To control the shape of fluids, [Mad,TKPR09] exert forces to fluids with control particles to attract the fluid to target shapes. [LCY*19] also uses a control particle system to guide the shape deformation of fluids. [HK04] uses a geometrical potential to coerce the fluids into target shapes.…”