互動式雪模擬與渲染

Abstract

在這篇論文中，我們提出了一種模擬和渲染動態雪的技術。雪的模擬是基於粒子和網格。移動中的雪用粒子來模擬，靜態和被覆蓋的雪轉換成網格單元。運用粒子間的彈簧來模擬雪易碎的特性。雪會依情況在粒子和網格單元間轉換。雪的渲染是依據Shell structure的方法呈現，每個粒子是用多層的shell mesh組成的，每層用不同的shell texture來呈現。Shell texture會記錄冰結晶在空間中的位置資訊。最後用Half-angle volume slicing的技術粒子間的光影。

In this thesis, we propose a method of simulating and rendering dynamic snow. Snow is simulated using a combination of particles and grids. Mobile snow particles are simulated using discrete element method. Piles of immobile and invisible snow particles are reduced and converted into grid cells. Particles are connected by springs to simulate the brittle properties of snow. A conversion method between snow particles and snow cells is presented. Each particle is rendered as a series of concentric, semi-transparent, textured shells containing samples of the ice crystal geometry. Half-angle volume slicing technique is used to compute the lighting between the particles. Using our rendering technique, we are able to replicate some of the visual effects of snow, such as rough surfaces and glittering effect.