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      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
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LargeJ

How to ray-trace individual hair strands

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Hello all,

I want to implement a ray tracer that models hair fibers as described by Marschner et al: "Light scattering from Human Hair Fibers (2003)". From reading several other papers I noticed that hair can be rendered explicitly and implicitly. Explicit rendering requires every hair strand to be rendered separately, but because hair fibers are very thin compared to the size of a pixel, there will likely be aliasing problems. I read a lot about using volume densities instead, but I do not entirely understand this idea.

I was wondering what techniques are generally used to ray-trace a hair fiber? My idea is that hair segments (curves) can be projected on the image plane. This way, you exactly know which pixels are affected and then apply pixel blending to render the fibers that affect the pixel. However, I have not been able to find a (scientific) paper explaining the best way to render individual hair strands using ray tracing. It looks like many people choose to treat the curves as thin cylinders and use oversampling to accomodate for the aliasing problems.

So, does anyone know how a single hair fiber is ray traced nowadays? The rendering should be physically accurate, so speed is not an issue at this point.
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(This is my understanding)

Volume density approach means that you're not necessarigly looking for intersections with rays against individual hair strands, but against an adaptive iso-surface, you terminate when the distance from the ray point to the hair is within a given tolerance, and that tolerance can be adapted based on distance from the camera so that aliasing, and need for super-sampling is decreased. (Aka as distance increases from camera, you can increase the tolerance so that the distance from ray to the hair strand remains roughly constant in screen space) Edited by luca-deltodesco
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