FXPHD – HOU232 – Creating Fire and Smoke Simulations in Houdini and Axiom

本课程由 Liam Whitehouse 讲授，介绍如何为中世纪欧洲战争场景中被摧毁的木制攻城塔创建详细的火焰和烟雾烟火模拟效果。课程详细介绍了 Houdini Pyro 工作流程，包括采购、创建烟火属性、模拟和调整模拟、使用烟火烘焙体积可视化模拟、设置材料并使用 Karma XPU 渲染烟火模拟。

它还涵盖了新的 Axiom GPU 稀疏解算器，这是一种非常快速且高效的模拟插件，可以显著减少 Houdini pyro fx 模拟的高细节模拟时间。会员还将学习如何在 Axiom 中设置来源、影响场、风、湍流、耗散、阴影和设置平流二次模拟，以创建精美细致的火焰和烟雾渲染，用于高端视觉效果镜头。

Liam Whitehouse 是一位澳大利亚高级视觉特效艺术家，自 2003 年以来一直从事 3D 行业。在过去的 21 年里，他参与过各种各样的项目，最近包括《糖豆人》中的环境、《海王 2》中的水下环境、《权力之戒》中的林顿森林、Disney Plus 上《猎鹰与冬日战士》的逼真峡谷环境、《哥斯拉大战金刚》的空心地球环境以及《阿凡达 2》中的摄影测量岩石。

第一节课：简介
课程内容概述以及如何仔细设置正确匹配的 Houdini、Axiom GPU pyro 解算器、Labs 工具和 Open Colour IO ACES 色彩管理版本。这将确保与所有软件完全互操作，以模拟和渲染所有类别。

第 2 课：不同 Pyro 节点概述和示例设置
在 Houdini 中，有许多不同的节点用于烟火模拟和设置。我们涵盖关键术语和工作流程，包括来源、粒子设置、烟火源属性、光栅化粒子、烟火解算器、添加噪音和细节、增强、燃烧、可视化火焰、缓存到磁盘和渲染前的烟火烘焙可视化。

第 3 课：设置详细的烟雾火工模拟和采购
本课程涵盖了烟火模拟的最重要元素，从头开始创建详细的烟雾模拟，然后逐步添加所有元素以了解它们的工作原理。我们涵盖了来源、粒子属性设置、将粒子光栅化为体积、烟火模拟设置以创建详细的滚滚烟雾，通过调整风、湍流、碎裂和温度，最后使用烟火烘焙体积输出可视化烟雾。

课程 4：设置具有快速逼真运动的火灾模拟
设置详细、清晰、快速移动的火焰的技巧和窍门，避免 VFX 中常见的柔和慢动作 cgi 火焰外观。我们将了解如何设置快速消散的烟火，以及如何调整速度、子步骤和湍流，以创建与真实世界参考镜头相匹配的逼真火焰。我们还设置了温度和衰减，以创建火焰的清晰边缘，并在最后步骤中将其与 Karma XPU 烟火着色器连接起来。

第 5 课：Karma XPU 中的 Pyro 材料设置概述和渲染
一旦模拟了火焰和烟雾并将其缓存到磁盘，我们就可以将其读入 Solaris 阶段，并将 MaterialX pyro 着色器设置到烟雾和火焰上，然后添加灯光和摄像头，以便在 GPU 上的 KarmaXPU 中进行渲染。我们将使用 HDRI 调整定向光和环境光，以创建不同的外观，然后

第 6 节课：Axiom GPU Solver 简介以及与 Pyro FX 的集成
Axiom 概述，它是业界领先的稀疏 GPU 加速体积流体解算器，用于视觉效果，与 Houdini Pyro 系统紧密集成。介绍如何使用 Axiom 和各种设置创建烟雾模拟以生成详细的烟雾。

第 7 课：如何使用来源和影响场来影响模拟
除了发出详细的烟雾和火焰之外，您还可以使用场来影响公理烟火模拟的属性，包括温度、速度、风、压力和燃料。我们来看看如何使用影响场来影响这些参数，以及如何影响自定义 VDB 对象。

第 8 课：利用噪音为攻城塔提供 Axiom 火力
我们创建了一个复杂的系统，用于将火焰投射到表面和物体上，使其中心温度高、湍流大，边缘温度低。我们还设置了一个动画程序噪声，为我们的模拟产生不同规模和形状的逼真火焰。

第 9 课：创造快速移动、细致的火焰
在本课中，我们将介绍创建照片级真实火焰所需的所有公理模拟设置。这包括来源设置、湍流、扰动和浮力以及噪声的规模和速度以及所有其他设置。

第 10 课：利用火灾模拟中的平流创建烟雾模拟
在创建了照片级高分辨率火焰后，我们接下来创建了具有不同分辨率和不同速度的单独烟雾，这些烟雾由火焰传播。由于烟雾更柔和，体积和面积也更大，因此将烟雾与火焰分开以创建可单独批准的独立模拟是有利的。

Duration 6h 9m MP4

Title: FXPHD – HOU232 – Creating Fire and Smoke Simulations in Houdini and Axiom

Info:
This course, taught by Liam Whitehouse, covers how to create detailed fire and smoke pyro simulation effects for a destroyed wooden siege tower, for a warfare scene set in medieval Europe. It covers Houdini Pyro workflow in detail for sourcing, creating pyro attributes, simulation and adjustment of simulations, visualising sims using the pyro bake volume, and setup of materials and rendering pyro sims using Karma XPU.

It also covers the new Axiom GPU sparse solver which is a very fast and efficient simulation plugin which can dramatically reduce simulation times for Houdini pyro fx simulations at high detail. Members will also learn how to setup sourcing, influence fields, wind, turbulence, dissipation, shading and setup of advected secondary simulations in Axiom to create beautiful detailed fire and smoke renders for high end visual effects shots.

Liam Whitehouse is an Australian based Senior VFX artist who has been in the 3D industry since 2003. He has worked on various projects over the past 21 years including most recently environments in The Fall Guy, underwater environments in Aquaman 2, Lindon forests in The Rings Of Power, photorealistic canyon environments for The Falcon and the Winter Soldier on Disney Plus, and the hollow earth environments for Godzilla vs Kong, as well as photogrammetry rocks in Avatar 2.

Class 1: Introduction
An overview of the content covered in the course and how to carefully setup the correct matching version of Houdini, Axiom GPU pyro solver, Labs tools and Open Colour IO ACES colour management. This will ensure complete interoperation with all software for the simulation and rendering of all classes.

Class 2: Overview of different Pyro nodes and example setups
In Houdini there are many different nodes used for pyro simulation and setup. We cover key terminology and workflows including sourcing, setup of particles, pyro source attributes, rasterising particles, the pyro solver, adding noise and detail, enhancements, burn, visualising flames, caching to disk and pyro bake visualisation prior to rendering.

Class 3: Setting up detailed smoke pyro simulation and sourcing
This class covers the most important elements of pyro simulation by creating a detailed smoke simulation from scratch and then adding on all the elements step by step to learn how they work. We cover sourcing, setup of particle attributes, rasterizing particles to volumes, pyro simulation settings to create a detailed billowing smoke, by adjusting wind, turbulence, shredding and temperature, and finally a visualisation of the smoke using the pyro bake volume output.

Class 4: Setting up fire simulation with fast realistic movement
Tips and tricks to setup detailed, sharp, fast-moving fire which avoids a soft slow motion cgi fire appearance that is all too common in VFX. We look at how to setup quickly dissipating pyro as well as adjusting speed, sub-steps, and turbulence to create a realistic fire that can match real world reference footage. We also setup the temperature and falloff to create defined clear edges of the fire and connect it with Karma XPU pyro shaders in the final steps.

Class 5: Pyro material setup overview and rendering in Karma XPU
Once our fire and smoke is simulated and cached to disk we can read it into Solaris stage and setup our MaterialX pyro shaders onto our smoke and fire and add lights and a camera to render in KarmaXPU on our GPU. We will adjust our directional light, env lighting using HDRI’s to create different looks, and

Class 6: Intro to Axiom GPU Solver and integration with Pyro FX
Overview of Axiom which is an industry leading sparse GPU-accelerated volumetric fluid solver for visual effects that tightly integrates with the Houdini Pyro system. Introduction to creating a smoke simulation using axiom and various settings to generate detailed smoke.

Class 7: How to use sourcing and influencefields to affect simulations
As well as emitting detailed smoke and fire you can also use fields to affect the attributes of the axiom pyro simulation, including temperature, velocity, wind, pressure and fuel. We look at how to affect these parameters using influence fields and influence custom VDB objects.

Class 8: Sourcing the Axiom fire with noise for the siege tower
We create a sophisticated system for sourcing the fire onto surfaces and objects so that it has a hot and turbulent centre and cooler edges. We also setup an animated procedural noise to produce different scales and shapes of realistic flames for our simulation.

Class 9: Created fast moving, detailed fire
In this class we go through all the axiom simulation settings to create photoreal fire. This includes the sourcing settings, turbulence, disturbance and bouyancy as well as the scale and speed of noise and all other settings.

Class 10: Creating smoke simulation using advection from the fire simulation
After creating our photoreal high resolution fire, we next create separate smoke with a different resolution and a different speed which is advected by the fire. Because smoke is softer and also larger in volume and area, it can be advantageous to separate the smoke from the fire to create independent simulations which can be approved separately.