Author Archives: Eric

CFP: IEEE CG&A special issue on material appearance

Passing on the word:

IEEE CGA special issue

Modeling and Rendering Material Appearance

Final submissions due: 1 July 2011
Publication date: March/April 2012

Modeling and rendering the appearance of materials is important in many computer graphics applications. Understanding material appearance draws on methods from diverse fields including the physics of light interaction with material (including models of BRDF, bidirectional reflectance distribution functions, and BSSRDF, bidirectional subsurface scattering reflection distribution functions), human perception of materials, and efficient data structures and algorithms.

This special issue will cover all aspects of material appearance in graphics, ranging from theory to application. Possible topics include (but are not limited to)

  • first-principle models for BRDF and BSSRDF;
  • procedural models of materials;
  • modeling of mesoscale material features including bumps, ridges, and so on;
  • measurement of material appearance including BRDF, BSSRDF, and BTF (bidirectional texture functions);
  • numerical simulation of material appearance;
  • new instruments for measuring appearance;
  • material-appearance models from photo collections;
  • new data structures for representing material appearance;
  • efficient rendering of BTF and BSSRDF;
  • new interfaces for designing material appearance;
  • methods for printing hard copies of material appearance;
  • psychophysics of material appearance with application to computer modeling;
  • material-appearance applications in industry such as the design of paints and coatings; and
  • nonphotorealistic rendering of material appearance.

Questions?

Contact Holly Rushmeier (holly@acm.org) or  Pierre Poulin (poulin@iro.umontreal.ca)

Submission Guidelines

Articles should be no more than 8,000 words, with each figure counting as 200 words. Cite only the 12 most relevant references, and consider providing technical background in sidebars for nonexpert readers. Color images are preferable and should be limited to 10. Visit CG&A style and length guidelines at www.computer.org/cga/author.html.

Please submit your article using the online manuscript submission service at https://mc.manuscriptcentral.com/cs-ieee. When uploading your article, select the appropriate special-issue title under the category “Manuscript Type.” Also include complete contact information for all authors. If you have any questions about submitting your article, contact the peer review coordinator at cga-ma@computer.org.

Seven Things for March 10th, 2011

I’m back from a NYC trip (highlight: went to the taping of the Jimmy Fallon show and saw Snooki & Laurie Anderson – now there’s a combo; if only they had collaborated) and a San Francisco trip (highlights: the Autodesk Gallery – open to the public Wednesday afternoons – plus the amusingly-large and glowing heatsink on a motherboard at the NVIDIA GDC reception). So, it’s time to write down seven other cool things.

  • A convincing translucency effect was presented at GDC by the DICE guys (there’s precomputation involved, but it looks wonderful); Johan Andersson has a rundown of other DICE presentations. Other presentation lists include ones from NVIDIA and Intel, which I need to chew through sometime soon.
  • Vincent Scheib has a quick GDC report, and a presentation on HTML 5 and other browser technologies (e.g. WebGL), with a particular interest in the handheld market. Vincent mentions the Unreal GDC demo, which is pretty amazing.
  • Intel has a nice shadows demo, showing the various tradeoffs with cascaded and exponential variance shadow maps. It compiled out of the box for me, and there’s lots to try out. My only disappointment was that Lauritzen et al.’s clever shadow tricks are not demonstrated in it! Their basic ideas center around the idea of a prepass of the scene. They get tight bounds on the near and far view planes by finding the min and max depths, and tighten the shadow maps’ frustums around the visible points. Simple and clever, large improvements in shadow quality in real scenes, and relatively easy to implement or add to existing systems. (thanks to Mauricio Vives)
  • Feed43: This is a nice little idea. It tracks any web page you want, and you specify what is considered a change to the page. When a change is detected, you’re given an RSS ping. Best part is, you can share any RSS feed created with everyone. Examples: Ke-Sen Huang’s great conference paper list, and The Ray Tracing News. If you make a good feed, let me know and I’ll pass it on here. (thanks to Iliyan Georgiev)
  • This one’s old, but it’s a great page and I found it worthwhile, a discussion of gamma correction and text rendering. The surprising conclusion is that gamma alone doesn’t work nicely for text (it does wonders for line antialiasing, as I hope you know: compare uncorrected vs. corrected). It turns out that things like TrueType’s hinting has been tuned such that antialiasing and gamma correction can be detrimental.
  • An interesting tidbit from the government report “Designing a Digital Future“: on page 71 is an interesting section. A sample quote: “performance gains due to improvements in algorithms have vastly exceeded even the dramatic performance gains due to increased processor speed.” They give a numerical algorithms example where hardware gave a 1000x gain, algorithms gave a 43000x gain, 43 times as much. (thanks to Morgan McGuire)
  • My Minecraft addiction has died down a fair bit (“just one more project…”), but I was happy to see Notch make a blog post with some technical chew, with more posts to come. He talks about a problem many apps are starting to run into, how to deal with precision problems when the terrain space is large. His solution for now, “it’s a feature!”, which actually kinda makes sense for Minecraft. He also starts to describe his procedural terrain generation algorithm.

SIGGRAPH 2011 Housing Reservations Open

Go get your reservation. Even if you think you have a 10% chance of going to SIGGRAPH 2011 this year, I recommend holding a room now. You can cancel the reservation later at no cost until July 21.

Me, I went with the Empire Landmark Hotel, as it was a good balance between price and distance (location also sounded good). The YWCA was very tempting, though – really, if you’re traveling alone (I’m with 2 others), it’s an incredible bargain ($99 a night) for a single person and has a noticeably higher rating than the Empire Landmark on TripAdvisor.

Oh, also, if you’re an interactive rendering type of person, don’t forget that HPG 2011 is colocated with SIGGRAPH 2011 and starts on August 5 (a Friday), so you might want to book from August 4th on. You can always carve off days from your reservation later. That said, choosing August 4th does trim down the available hotels a bit. For me, HPG is a must-attend; when it was colocated with SIGGRAPH in 2009 (it alternates between SIGGRAPH in North America and EGSR in Europe) I found it offered more relevant papers than all of SIGGRAPH itself.

Books at GDC

I haven’t listed out new(ish) books for awhile, so here are a bunch. If you’re at GDC, you can take a look at most of them in the exhibitors hall. There’s also a high-quality volume free for download (or pay $81.38, if you prefer), so read on.

Three that are hot off the press:

GPU Pro 2, Wolfgang Engel ed., AK Peters – The next in the series (which continues the ShaderX series), and it looks like there’s a fair bit of chew in there. See the approximate table of contents here. Me, I’m particularly interested in the MLAA article; there’s a preview, moview, and more here.

GPU Computing Gems, Emerald Edition, Wen-Mei W. Hwu ed., Morgan Kaufmann – the GPGPU topics covered are all over the map, and unfortunately the two reviews on Amazon are not positive, but I’d like to page through it nonetheless and see what it’s like. Table of contents and sample chapters here.

Game Engine Gems 2, Eric Lengyel ed., AK Peters – More nuts and bolts and about game engines in general, take a look at the table of contents here.

There are also a few other graphics-related books that have come out in the past year that we haven’t mentioned here yet:

Game Physics Pearls, Gino van den Bergen and Dirk Gregorius ed., AK Peters – I’m not a user of game physics so can’t really judge this one, but thought it nice that the book has a progression to it: there’s an introductory chapter about the field, then practical articles about collision detection and simulation of various types of physical phenomena.

Polygon Mesh Processing, Mario Botsch, Leif Kobbelt, Mark Pauly, Pierre Alliez, Bruno Levy, AK Peters – This is a serious overview of research done on mesh-related algorithms, starting with data structures and covering such topics as smoothing, simplification, mesh repair, and deformations.

The rest are not directly related to interactive rendering, but are books I’ve wanted to page through. They’re all from Springer, who doesn’t appear to be exhibiting at GDC this year, so I guess they’re mostly be for sampling online:

Computer Vision, Richard Szeliski, Springer – Written by an expert in the field, I’ve heard this is a good guide to the subject. Super cool thing: the final draft of this book is free for download on his website. Much of Chapter 3 looks like a good read for interactive rendering programmers.

Mathematics for Computer Graphics, John Vince, Springer – I like to see such books, and have heard this one’s pretty good. It certainly starts out from the basics, though some topics covered seem unrelated (at least to me) to graphics.

Production Rendering, Ian Stephenson ed., Springer – definitely not interactive rendering, but it sounded like an interesting collection of articles from seven experts in the field. The last chapter in particular, “Rendering Gems”, looks pretty chewy. Perversely, Amazon’s “Look Inside” does not show you all of the Table of Contents, but Google’s excerpt does. Update: this turns out to be an old volume from 2004 I hadn’t noticed before (Springer books are usually too expensive for me, so I don’t tend to track them), one that Amazon mistakenly lists as having come out in November 2010 – see the comments below.

I’m betting I’ve missed other new books, so let us know by adding a comment.

Photos from I3D 2011

Provided by Mauricio Vives: feast your squinties. Lots of headshots, which I’m sure the speakers (and their moms) will appreciate. I certainly do; it’s great putting a face to a name.

Also, save the date: as the last slide shows, March 9-11 2012 is the next I3D, in Costa Mesa, California. I’m suitably impressed that next year’s co-chairs (Sung-Eui Yoon and Gopi Meenakshisundaram) already have a place and date. This was possible since they’re colocating I3D to directly follow IEEE VR, which is March 4-8.

One photo, “Carlo’s Models“:

NPAR Call For Papers

The ACM Non-Photorealistic Animation and Rendering Symposium has put out its call for papers. NPAR alternates its location each year between Annency, France (which is lovely) or colocated with SIGGRAPH (which is convenient for many of us). This is a SIGGRAPH year, in Vancouver (lovely and convenient). NPAR takes place the weekend before, colocated with Sketch-Based Interfaces and Modelling (SBIM) and (new this year) Computational Aesthetics (CAe).

How to Make an Ebook

Here’s a short guide on creating decent ebooks from scans using Adobe Acrobat. This will not be of interest to 98% of you, but I want to record it somewhere for those of you who may do this in the future. It is written by Iliyan Georgiev, who made the recent PoDIS ebook. Comments are welcome, as usual.

The one piece of software you’ll need that can’t be downloaded for free is Adobe Acrobat, though even this application has a 30-day free trial.

1. Scan the pages of the book using a scanner (a digital camera is a good alternative).

2. Crop the scanned images (and split the pages, if you scanned two pages at once). It’s better for an ebook to have smaller page margins. Also, cropping removes black areas and other artifacts resulting from scanning. An excellent (JPEG-only) batch cropping tool for Windows is JPEGCrops. It has some disadvantages, however, so in practice it’s best to use JPEGCrops to estimate approximate cropping parameters (width, height, x-offset, y-offset) and XnView‘s batch processing mode for the actual cropping. Both applications are free and have portable versions.

3. Assemble all images into a PDF file. Adobe Acrobat has an option to combine multiple files into a single PDF. Use the highest quality settings for the creation.

4. (OPTIONAL) Rearrange/merge/delete pages. Acrobat has excellent tools to achieve these. This can be useful for books that are published in two volumes or for extending the book with additional information, such as errata listings, images, high quality cover pages, etc.

5. Manage blank pages. It might be tempting to delete blank pages inside the book. Such pages are always intentionally left blank by the publishers, as they are important for the printing order. This is particularly important for the first few pages, as well as for the chapters. Many books are created in such a way that all chapters start on an even/odd page, and the large majority have the inner pages typeset for being printed on a specific side (left/right). If you want to optimize the page count anyway, keep in mind how the book would appear when printed out (also using “2 pages per sheet” printing).

6. Number the pages. This is an often-overlooked, but very useful, option. Apart from the default page numbering, the PDF format supports logical page numbering. This can be used to synchronize the PDF page numbers with the actual book page numbers. This is very easy to do in Acrobat and should always be done. To do this, select the necessary pages, right click on them and choose “Number Pages…”.

7. Run OCR (optical character recognition) on the PDF. This is an extremely easy way to make your scanned pages searchable and the text copy/paste-able. Acrobat has a good and easy to use built-in OCR tool. You will find it in the Document menu (Tools pane in Acrobat X). Be sure to disable image resampling, as by default OCR will resample the images, which can easily increase the file size by a huge amount! Keep in mind that OCR is a compute-intensive process and can easily take a couple of hours for a larger book.

8. Optimize document. Acrobat has an option to optimize scanned documents. This runs some image-processing algorithms on the scanned images and compresses them aggressively when it detects text. This is a vital step to keep the size of the document low. It can reduce the file size by a factor of 20! It will also make the antialiasing to look better when pages are minified, if the resolution of the original scans is high enough. This process is also compute-intensive and can easily take an hour for a larger book.

9. (OPTIONAL) Reduce the file size further by using Acrobat’s other optimization options, from which the image downsampling is the most important.

At this point the most important steps are done and you can end here and go to sleep if you see the sunrise through the window. Go on if it’s only 4 AM.

10. (OPTIONAL) Setting the initial view. Open the document properties on the Initial View tab. Here, you can set the initial page, zoom level and which panes (e.g. the bookmarks pane, see below) should be active when the document is opened.

11. (OPTIONAL) Create a PDF table of contents (TOC). The PDF format has a useful (hierarchical) bookmarking feature with a dedicated Bookmarks pane which exists also in Adobe Reader. This feature can be used to reconstruct the book’s TOC for easy document navigation. One simple way to achieve this is the following:
11.a Go to the book’s Contents page, select the chapter title’s text and hit CTRL+B (or right click and choose to add a bookmark from the context menu). Repeat this for each chapter.
11.b Structure the created bookmarks. Rearrange the bookmarks to follow the order and structure of the book’s TOC.
11.c Link the bookmarks to pages. To do this, go over all pages of the book sequentially and every time a new chapter starts, right click on the corresponding bookmark and set the destination to the current page.

12. (OPTIONAL) Create hyperlinks inside the document. The PDF format also supports hyperlinks which can perform actions (e.g. jump to a page or a web site) when clicked. Links can be either rectangles (drawn with a corresponding tool) or text. To create text links, select the text, right click on it and choose to crate a link. There are options to set the link’s appearance and behavior.

You’re done! You have the perfect ebook and you’re late for work!

Thanks, Iliyan!

In my post about PoDIS now being free, I asked for a volunteer to reformat the two PDFs into a nicer single file. Iliyan Georgiev, a PhD student at the University of Saarland, stepped up and took over. After a few iterations, with Andrew and me providing feedback, he’s made an excellent new version of “Principles of Digital Image Synthesis”. Download this new version from here (right-click and “Save link as…”).

This new version is much superior to the one on Google Books. It’s a single, searchable file (the Google Books version is just a scan without any OCR), it has a hyperlinked table of contents (actually, two of them), and has all errata folded into the text.

Along the way I learned a new trick from Iliyan: you can put PDFs (or any file type at all) into your Google Docs area and make them entirely public, which is how this version of the book is distributed. This is good news for all researchers: you can now host your publications in your own account. No hassling with the I.T. guys to get an account, no fuss if you move to another institution. Now no researcher needs to be held back by “it’s not company policy to give public web space” or other bureaucracy. Having a web site is nicer, but hosting in this way is free and simple. You can host up to a gigabyte for free.