Xu Wang

selected publications

1. CGI

   XProtoSphere: an eXtended multi-sized sphere packing algorithm driven by particle size distribution

   Wang, Xu*, Fujisawa, Makoto, and Mikawa, Masahiko

   The Visual Computer 2023

   Abs Code Website

   The sphere packing problem, which involves filling an arbitrarily shaped geometry with the maximum number of non-overlapping spheres, is a critical research challenge. ProtoSphere is a prototype-oriented algorithm designed for solving sphere packing problems. Due to its easily parallelizable design, it exhibits high versatility and has wide-ranging applications. However, the controllable regulation of particle size distribution (PSD) produced by ProtoSphere is often neglected, which limits its application on algorithm. This paper proposes a novel PSD-driven technique that extends the ProtoSphere algorithm to achieve multi-sized sphere packing with distribution-specific characteristics, as dictated by a pre-defined cumulative distribution function. The proposed approach improves the controllability and flexibility of the packing process, and enables users to generate packing configurations that meet their specific requirements. In addition, by combining the relaxation method with the ProtoSphere algorithm, we can further improve the packing density and ensure the average overlap below 1{\%}. Our method generates multi-sized particles that can be used to simulate the behavior of various granular materials, including sand-like and clay-like soils.

2. SCA

   Visual Simulation of Soil-Structure Destruction with Seepage Flows

   Wang, Xu*, Fujisawa, Makoto, and Mikawa, Masahiko

   Proc. ACM Comput. Graph. Interact. Tech. 2021

   Abs Code Website

   This paper introduces a method for simulating soil-structure coupling with water, which involves a series of visual effects, including wet granular materials, seepage flows, capillary action between grains, and dam breaking simulation. We develop a seepage flow based SPH-DEM framework to handle soil and water particles interactions through a momentum exchange term. In this framework, water is seen as a seepage flow through porous media by Darcy's law; the seepage rate and the soil permeability are manipulated according to drag coefficient and soil porosity. A water saturation-based capillary model is used to capture various soil behaviors such as sandy soil and clay soil. Furthermore, the capillary model can dynamically adjust liquid bridge forces induced by surface tension between soil particles. The adhesion model describes the attraction ability between soil surfaces and water particles to achieve various visual effects for soil and water. Lastly, this framework can capture the complicated dam-breaking scenarios caused by overtopping flow or internal seepage erosion that are challenging to simulate.