Publications and Presentations

Changing the Drawing Process in the Light Of New Technology (R. Pride, W. Hargreaves and I. Stephenson)

The two set designers who I worked with on the set modelling software presented their experiences of working with the new tools to the Scenography working group.

Presented At TaPRA 2010 (Cardiff)

Screen-Space Re-Rendering for the Simulation of Concert Lighting

The limitations of our previous relighting software was that it was only effective for static lights. This extends to to support moving head lights, allowing multiple lamps with full volumetrics and complex gobos to be updated interactivly on modest hardware.

Presented At Eurographics UK TPCG10 in Sheffield.

Computer Modelling of Theatrical Sets (I Stephenson and R. Pride)

Lighting simulation packages aimed at theatre are limited by the need to actually develop CG models of the stage area - something traditional set designers are ill-equipped to do. We therefore developed software which could be used by set designers with minimal training.

Presented At Eurographics UK TPCG10 in Sheffield.

Simulating diffraction limiting in a pinhole camera

This formal write up of the pervious siggraph poster.

Published in the Imaging Science Journal: June 2009

Digital Relighting for Stage Use

Digital relighting is a great party trick, but hasn't really found much use. By hooking up a hardware accelerated relighting tool to a DMX lighting rig, we can quickly capture stage lighting, then preview the results of adjustments in real time when stage access is unavialble. This can be used either in pre-production, and during performance.

Updated and expanded versions of this work was presented at Eurographics UK TPCG09.

Hardware Accelerated Shaders Using FPGA (Luke Goddard and Ian Stephenson)

Graphics hardware isn't really suited to production rendering, so high quality hardware accelerated rendering is difficult. Custom hardware solutions are financially impractical. FPGA allow custom hardware to be generated at run time, allowing rendering hardware to be customised, not just for generic rendering, but for each surface in each scene. RenderMan shaders for each surface are compiled to hardware allowing surface illumination to be calculated at true hardware speeds.

Updated and expanded versions of this work presented at Eurographics UK TPCG09.

RenSH - Rendering in Shell Script

RenSH is a RenderMan compatable renderer written in shell script. Why? Because it's possible!

Presented at the Pixar User Group, SIGGRAPH 2008.

A Per Grain Simulation of Film

Statistical models of film grain simply don't work - grain isn't simply noise, rather is's embeded in the stucture of the image. Here were sumulate the latent image, and development process of an entire negative, one grain and one photon at a time.The results not only appear visually appealing, but sensiometric properties such as the characteristic curve, Granularity and reciprocity failure emerge without being explcitly programmed into the simulation.

Presented as a Poster at Siggraph 2008. PDF

Digital Relighting for Stage Use

Digital relighting is a great party trick, but hasn't really found much use. By hooking up a hardware accelerated relighting tool to a DMX lighting rig, we can quickly capture stage lighting, then preview the results of adjustments in real time when stage access is unavialble. This can be used either in pre-production, and during performance.

Presented as a Poster at Siggraph 2008. PDF

Hardware Accelerated Shaders Using FPGA (Luke Goddard and Ian Stephenson)

Graphics hardware isn't really suited to production rendering, so high quality hardware accelerated rendering is difficult. Custom hardware solutions are financially impractical. FPGA allow custom hardware to be generated at run time, allowing rendering hardware to be customised, not just for generic rendering, but for each surface in each scene. RenderMan shaders for each surface are compiled to hardware allowing surface illumination to be calculated at true hardware speeds.

Presented as a Poster at Siggraph 2008. PDF

Simulating Film Grain using the Noise Power Spectrum

Adding grain to simulated images makes them look more exciting. While its relativly easy to add some noise, here we use the principles developed by imaging scientists to produce grain which is theoretically "correct". While the results are usefull, they also illustrate the limitations of current photographic theories of grain.

Text

This work is published in Eurographics UK 2007

Essential RenderMan 2nd Edition

It took forever to make it to press, but we finally ironed out all the bugs, and the new edition looks great! The content is basically the same, but everything has been rewriten/edited to improve clarity, and the images reworked so that they're FAR clearer than the first edition.

You can buy it from Amazon.

Improving Motion Blur: Shutter Efficiency and Temporal Sampling

An extended version of the SIGGRAPH sketch is published in the January 2007 edition of the Journal of Graphic Tools. It includes an improved sample distribution function which allows the efficiency to be set from 50 to 100 percent

Shutter Efficiency and Temporal Sampling

Presented as a sketch at SIGGRAPH 2005. Motion blur in rendering systems is typically based upon a perfect shutter. Lower shutter efficiency, as exhibited by real leaf shutters, can produce better images, both in theory and practice. This can be implemented trivially, and without performance cost in virtually any renderer.

Text Presentation

A Real Virtual Pinhole

To be presented as a poster at SIGGRAPH 2005. Virtually every publication on rendering refers to a "theoretical pinhole camera". However these bare little or no relation to a real pinhole camera. Here we consider the pinhole camera in a little more depth, and discover some interesting results...

Text Poster

Production Rendering, Design and Implementation

This book on rendering considers REAL rendering systems, integrating complex geometry, procedural shading, and global illumination. It is edited by Ian Stephenson, but each chapter has been written by a software developer currently working on commercial rendering software. It includes contributions from Mark Elendt(Side FX), Rick LaMont(DotC), Scott Iversion(SiTeX Graphics), Paul Gregory(Aqsis), Jacopo Pantalioni(LightFlow), and Matthew Bentham (ART).

You can order (or just get more info) from the Springer web site. It's also available through amazon, and all good bookshops.

RenderMan for Research at TPCG04 June 2004

I'll be presenting an introduction to RenderMan, combined with examples of how RenderMan can help the researcher at Theory and Practice of Computer Graphics 2004. The half day course will cover an overview of the RenderMan API, with particular emphasis on integrating new techniques into existing renderers, and consideration of alternative applications of the RenderMan interface, beyond standard production rendering.

Rendering Smoke with particle maps

Presented at the Pixar User Group, SIGGRAPH 2003. By storing particles in a photon map-like data structure, they can be ray marched in an atmosphere shader. The resulting shaders are fast, and controllable. (PowerPoint)

Implementing RenderMan on the Sony PS2

Presented at SIGGRAPH 2003. This sketch considers how the PS2's graphics hardware can be exploited to speed up production rendering. If you have a PS2 Linux kit you can get the executables from the PS2 Linux site. (pdf) (PowerPoint)

Essential RenderMan Fast

Essential RenderMan Fast is an introduction to RenderMan I wrote for the Springer Essential series. It covers RIB, the C APi and shading, in a nice and friendly fashion. More info and code for all of the examples is available.

You can buy it directly from the publisher. It's also available from Amazon.

Handbook of Computer Animation

I few years ago I was invited to contribute a chapter on rendering to this collection of essays. I chose to take a practical approach and wrote about the problems I'd encountered writing Angel. The resulting chapter basically provides a roadmap for anyone planning to write a basic renderer, with emphasis on the shading engine.

It took over two years for the book to reach print, but its now its available from Amazon, or directly from Springer.

Compressing RIB files using DIFF

Presented at the SIGGRAPH 2002, Pixar users group. This discusses how inter-frame dependencies can be exploited to reduce storage requirements durning rendering. (pdf)

Anti-aliasing Perlin Noise

Presented at SIGGRAPH 2001. In Abstracts and applications. Inoise is a filtered verision of the standard Perlin Noise function, and produces signifigantly better images than simple frequency clamping. (pdf)

Vector Texturing (John Haddon and Ian Stephenson)

Presented at SIGGRAPH 2001. In Abstracts and applications. Vector texturing demonstrates how vector graphics may can be applied as textures in rendered scenes. (pdf).

Buffy, an SL Development Environment

Presented at the Digital Content Creation conference, Bradford 2000. This discusess the contruction of a debugging tool for RenderMan shaders. Published by Springer. (pdf)

Creatures and Spirals (Ian Stephenson and Richard Taylor)

Long before I got interested in graphics, I researched SIMD architectures, similar to those found in shading engines. This paper was published at the Euromicro workshop on parallel and distributed processing, in 1994. (pdf).

For completness you can also download a copy of my DPhil thesis (pdf).

Ian Stephenson.
DCT Systems
NCCA,Bournemouth University