《Houdini流程化道路制作教程2》cmiVFX Houdini Procedural Road Creation 2

本教程是由cmiVFX机构出品的Houdini流程化道路制作教程，时长：4小时29分，教程使用软件：Houdini，作者：Kim Goossens Goossens，格式：MP4视频，语言：英语。

我们希望能够避免过多的虚拟汽车事故因此我们就来让道路更安全一些。你需要在放置防撞围栏前了解到需要考虑哪些元素。你将会学习到使用例如campare, modulo & import属性等VOPS来程序化制作防撞围栏。

Houdini 是一个特效方面非常强大的软件。许多电影特效都是由它完成：指环王中“甘道夫”放的那些“魔法礼花”，还有“水马”冲垮“戒灵”的场面，后天中的龙卷风等等，a52的汽车广告，反正只要是涉及DD公司制作的好莱坞一线大片，几乎都会有Houdini参与和应用。

Houdini不光只适用于视觉特效的制作，随着HOUDINI适用于各种平台，并且出现了很多的HOUDINI培训教学，HOUDINI开始进入了动态图像设计领域。因为其自身的流程化特性，加上其强大的动力学系统，让HOUDINI在数据可视化方面占有一席重要的地位，让图形设计师能够通过它表达自己的观点。

cmiVFX Houdini Procedural Road Creation 2
We want to avoid to have too many virtual car casualties lets make those road virtually safer. Like everything you want to create procedurally you need to understand what the basics are making the object what it is. You will get an overview what element to consider when placing crash barriers. You'll learn how to procedurally create the placement of the crash barrier by using Vops such as compare, modulo & import attribute

Building The Crash Barrier
A novel method will be presented to cut a spline up into several segments to be used later as crash barrier placement holders. The crash barrier cannot be build without it's basic components. You'll prepare the basic profiles in order to create the crash barrier. You'll see how to create an absolute space carve digital asset for creating proper placement of the crash barrier support poles.

Setting Relationships Between the Shape

A digital asset works best when its energy lines and chakra's are all in place. To create a good procedural shape you must find as much relationships between the shapes as possible. You'll be explained how to build these relationships and you'll learn how to use expressions and variables to create the relationships between the created shapes.

Grouping Elements For UV's
Like stated before a procedural model without proper uv's and textures loses a lot of it's power. In this session you will learn how to create procedural groups of the crash barrier in relation with the spacing between the support poles. You'll see how to get parts from a texture by using random selection within a forloop.

Setting Relationships Between the UV`s and the Texture
Just like with creating the relationships between the geometry you'll have to constrain the uv's to specific boundaries. Using expressions you'll gain experience into controlling the uv's in such ways that they access specific parts of the texture allowing you to create complex procedural mappings. You'll see techniques to to simplify expressions by braking them up using spare parameters. Furthermore you'll learn how to "steal" uv positions from the crash barrier for the support poles using the raysop.

Completing the Graph into a Fast Usable Digital Asset
One of the most important things to consider when creating your tools is that you want to provide the user with fast and clear feedback. It is all about communication with the user. Here you'll learn techniques to provide fast feedback when manipulating the asset and how to create a global scale controller so that you are still able to work with normalized values.

Prototyping on a Simplified Version
Mountains are big obstacles... Time to get a big drilling machine and a bridge builder. In this section you get to learn how to create the spline segments you need for creating the tunnels and bridges you need for the landscape. Performance is always an issue if you want to build a good functioning tool set. Learn how to use the performance monitor to compare various strategies in your modelling.

Finalizing Graph To Asset
You have to cross a pond a few meters wide, are you going to build the Golden Gate bridge for that? This section you will finalize the digital asset and it's functions. You'll measure the sections lengths in order to make choices what bridge to use possible. As always you'll finish the digital asset into a versatile tool by upgrading the tool that it works on a 3 dimensional landscape using a raysop, by creating a proper interface and by creating relationships between the parameters. You'll be proposed with some ideas how to extend the tool to more functionalities.

About The Author
Kim Goossens is a 38 years old belgian CG-artist who is working as a freelancer and CG-instructor with a long history in CG-graphics starting back at 1989 He became quite known for his creation of the GIRL later adopted by DAZ3D. He is currently teaching Houdini procedural modeling for games at the IGAD program at the NHTV University of Applied Sciences. While working on various game projects and commercials both as Art-director and technical artist, he gained a profound knowledge of tools such as Maya, Max, Zbrush, Modo, shake and Houdini. His biggest passion has always been to research strategies to increase production and quality, which has led him to research procedural modeling.

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