Fluid simulation is an essential tool to produce realistic looking animations. In particular, Lagrangian simulations offer interactive computation times with an easy integration of the two-way interaction with rigid bodies. However, the interactivity is lost for larger scenes even if only the areas around the bodies have any visual interest. In this paper, we present a novel approach to quickly initialize additional fluid in a rest state in simulations with any 3D boundary shape and able to preserve any already existing fluid. Our approach only uses the density property of the particles to allow compatibility with any smoothed-particle hydrodynamics (SPH) simulation scheme and any boundaries model. This initialization method is fast enough to allow the initialization of new fluid volumes interactively while the simulation is running. We showcase our approach by proposing a method to create a dynamic simulation window, allowing the restriction of simulating the fluid only around moving objects. We propose multiple experiments to demonstrate the capabilities and performance of our approach.

中文翻译：

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用于平滑粒子流体动力学模拟的流体初始化和动态窗口

流体模拟是制作逼真动画的重要工具。特别是，拉格朗日模拟提供了交互式计算时间，并且可以轻松集成与刚体的双向交互。然而，即使只有身体周围的区域具有视觉兴趣，较大的场景也会失去交互性。在本文中，我们提出了一种新颖的方法，可以在任何 3D 边界形状的模拟中快速初始化静止状态下的附加流体，并且能够保留任何现有的流体。我们的方法仅使用粒子的密度属性，以允许与任何平滑粒子流体动力学（SPH）模拟方案和任何边界模型兼容。这种初始化方法足够快，可以在模拟运行时交互式地初始化新的流体体积。我们通过提出一种创建动态模拟窗口的方法来展示我们的方法，该方法允许仅模拟移动物体周围的流体。我们提出了多个实验来证明我们方法的功能和性能。