Reading Due: Monday, April 27, 11:59pm (for class discussion April 28)
Canvas Discussion: Reading 22A on Canvas
We’ve been avoiding 3D for most of class. We can’t do it forever. While using 3D for visualization has its problems, sometimes its important (if we’re trying to show 3D phenomena), and sometimes it can be useful.
The required readings will give you a sense of how we see 3D. The focus is on the perception part. What cues do we use? What can we or can’t we measure visually?
We don’t really have much time in class to discuss how to make pictures that best help people see depth. I have some readings, but we won’t get to them. They are listed below in case you are interested.
Required Readings:
- Chapter 5 of Ware’s Visual Thinking for Design (this covers more than 3D, but the non-3D parts are short).
- James Todd. The Visual Perception of 3D Shape. Trends in Cognitive Science. 2004. A nice, compact article. It focuses on a few cues.
For the discussion… In your initial posting discuss why showing 3D is hard in a picture, but more significantly, what this should mean for making visualizations of 3D things. (when to use 3D? when to avoid it?) In the discussion, try to think of what to do in those cases when you need to show things in 3D. You’ll figure some out, you’ll see some in the seek and find, you’ll hear some ideas in class, or you can look at some of the things below. If you read some optional readings, say so.
As far as optional readings… artists have dealt with the problem of trying to convey depth in a picture since, well, I’ll let an art historian answer that, but let’s just say a long time. Painters and illustrators have all kinds of tricks. Photographers and filmmakers use light and camera position and other things. Computer Scientists have tried to pick up some of those tricks and systematize them.
This is a chapter of the “Guild Handbook of Illustration” that helps illustrators learn to convey 3D shape in their drawings. A lot of it is about how to think about how light helps you perceive shape (and it does so with fabulous examples). When they start talking about the actual techniques (like how to use charcoal to make the pictures), it’s a little less interesting.
- Light on Form (Chapter 4 of the Guild Handbook of Illustration) by Jessup and Mascaro. (CS protected reader) (box)
Some things that apply well to Vis:
- Amy and Bruce Gooch. Using Non-Photorealistic Rendering to Communicate Shape. SIGGRAPH ‘99 course notes here. (this is better than the original, but seminal paper. you don’t need to read it in detail – just skim through the motivation and look at the pictures).
- Cipriano and Gleicher. Molecular Surface Abstraction.
- Look at the light collages web page (but it links to the initial version of the paper – if you want to read more, check below).
I really wanted to add a few things that show how to effectively use the cues in visualization. But this is just so huge and broad that I don’t know where to start. I’ll mention some of my favorites (some of these are seminal pieces, where there is lots of follow on. some of these are:
- Lee, et al. Geometry-Dependent Lighting. IEEE Trans of Vis and Comp Graphics. (ieee official version). Note: this paper is the extended version of the original Light Collages paper.
- SIGGRAPH 2008 Course notes “Line Drawings from 3D Models” http://www.cs.princeton.edu/gfx/proj/sg08lines/ – These are nice slides that summarize the topic very well.
- DeCarlo, et al. Suggestive Contours for Conveying Shape. Proc. SIGGRAPH 2003. (pdf) (project). The 2003 paper is really seminal, the web page lists some of the follow-ons.
- Linedemann and Ropinski. About the Influence of Illumination Models on Image Comprehension in Direct Volume Rendering. IEEE Vis 2011. (page here)
