Here’s a classic image you’re probably familiar with, which is having its 40th anniversary:

I recently joined Reddit’s Raytracing feed, where I noticed it recently here, in Reddit’s Vintage CGI feed. I’d been playing with a real-time demo of this scene in OptiX 7, as it’s a sample program, optixWhitted. Examining that demo, it pointed out something that never dawned on me: the glass ball is actually mostly hollow, not solid glass!

To conclude, here’s a physical homage to the paper, with various transparent balls I have lying around on its first page. The one on the left is a glass shell, though quite wobbly in its thickness.

And if you just can’t get enough, here’s one with a plastic shell instead, which is more uniform but where the shell gets thicker toward its bottom (in the upper right part of it in this view).

I’ve been collecting too many links, with all of them begging me to share them. Here’s the triage:

• High Performance Graphics 2020’s call for participation is up. Key due date is April 16th (but you need to register the paper 3 days earlier than that). Retweet here.
• A high-res scan of a Nefertiti sculpture is now available. The story of it being freed up after a three-year effort is a good read, with a knee-jerk “we own it” attitude by the museum. I hadn’t heard of “the gift shop defense” before, and them carving a CC license in the base is pretty ironic, given how much they were defending not releasing it. He’s now pushing on the Musée Rodin for The Thinker. The Nefertiti file is in OBJ format with textures – it’s pretty nice, 12.8M tris. Download from the page using the link in the upper right, despite what the text below says; you can also view and download it on Sketchfab. (thanks to Adam Marrs for the link)
• Fascinating inverse rendering applications with Mitsuba2’s differentiable renderer – see the video from 2:38 to 4:50 in particular. Code’s not available yet.
• Trying to explain ray tracing to your relatives during the holidays? Of course you are. Here’s my contribution to the cause (or with Mandarin subtitles), in good part based on Pete Shirley’s Intro to RT talk (see links at the bottom of the page). Tweeted here.
• Thanks to a number of people, much of the ancient globillum mailing list archive is now available for download. If you know of a good email text file viewer, please let me know.
• I’m in the wrong field. People research the rubber pencil illusion, about the only magic trick I learned as a kid. Research into the RPI is here and here, which conclude that the pencil’s appearance of rubberiness is affected by different factors. This so needs a good three.js demo. I also want to see a character in some expansion of the game Control explain how this phenomenon is actually a paranormal event.
• Someday the photographer for your wedding will ask “crowd-source point cloud or laser scan?” – article; model on Sketchfab.
  

I’m assuming you read Jendrik Illner’s links collections, and Matt Pharr’s blog, among others. Here’s seven other things for today:

• Wolfgang Engel and company have released on Github The Forge, a cross-platform path tracer.
• Painting with CSS and HTML. Tres Zen: “Smith has a stringent rule that leaves this former web developer a little flabbergasted: all elements must be typed out by hand.”
• Such a simple shadertoy, 5 lines of code. I feel like this should be a final exam question, “how does this work?” (and I’d rather not take that test…).
• Sea-Thru color corrects so that you can see what aquatic life looks like when unfiltered by sea water.
• The worst Stack Overflow rendering-related answer in the world.
• Yet another new rights issue: who owns a celebrity’s appearance after they die, and for how long?
• I’ve enjoyed playing with display.land, a free phone app from Ubiquity6 that does a stereogrammetric capture of objects or spaces. You can post and share scans, and the explore interface is nice and intuitive on the phone (use one, two, and three finger touch gestures). You can download the data set to OBJ, gtTF, and PLY file formats. Here’s an example, which is hardly the best scan but looks nice & artsy in Microsoft’s 3D Viewer. I like that the pic below caught our RTR book’s cover.

Like the title says, and get it here. A few important errata for Chapter 3 were reported by a reader, Ebor Folkertsma, and so have been fixed by Tomas in this newest PDF, as well as fixing the caption for Listing 27-2. Let us know of any bugs you find so we can fix them: erich@acm.org

I just finished The Case Against Reality – didn’t love it. But it did have some tidbits about perception that were intriguing, such as the split-brain patient who was atheist on one side of the brain; the other, religious.

Reading it reminded me of stories about perception in two other books, which I want to pass on here. The first is from The Forest People, a lovely older book in which an anthropologist studies the Mbuti pygmy people, living with them for three years. Here he travels to grasslands with a friend from the tribe, who had never been outside the jungle before.

How are our own perceptions affected by our upbringing? How does more use of screen and virtual reality affect us? Perhaps it makes graphics easier, in some sense? I recall when physically based shading models started to replace Blinn-Phong, people complained that things didn’t look right with the new models, even though they were more realistic.

Next is a little experiment described in Incognito, which is the best bathroom book ever – there’s something new every few pages.

This makes me wonder a bit about lag & latency and how they’re best measured, or can be mitigated.

Anyway, both books are wonderful, and I had to resist adding the stories about the sacred drainpipe and about chicken sexing.

The I3D Call For Papers is up: http://i3dsymposium.github.io/2020/cfp.html

Key dates:
13 December 2019 Paper submission deadline
20 December 2019 Extension for re-submissions (see details above)
10 February 2020 Notification of committee decisions
24 February 2020 Camera-ready deadline for accepted papers
9 March 2020 Poster submission deadline
5-7 May 2020 Conference at ILM in the Presidio, San Francisco

I’m posting because I gave a lecture on ray & path tracing last Monday, and at the end gave a little career advice, at the request of the people running the class. One thing I ranted about was getting LinkedIn invites without any explanation. I did say to the audience, students, that they could ask me for a connection, if they wanted. I guess I didn’t make it clear that they, too, should add an explanatory note – “loved your lecture, you’re the best person on the planet” or whatever – as I then received two invites without any notes that I tracked down as being students at the lecture (and so accepted). Next time I’ll be clearer…

I get a lot of LinkedIn invites – I suspect most people do. My rule is I accept if (a) I clearly know you or (b) you work for the same company as I do or have some other obvious direct connection or (c) you added a little note as to why we should connect.

I see varying advice on this. LinkedIn itself blogs on the topic, saying not to connect to random people. But most of the people who want to connect are semi-random – they usually are interested in computer graphics. Some site with an icky (to me) URL of linkedinriches.com (with “$” for that final “s” on the website itself) says I should accept everything except the utter randos, which does have a logic to it – who really cares who connects? But, if I get a note from the inviter, I’ll go with the assumption that I know them somehow. And if I see I have a connection with someone, I’ll assume I can contact them, as we somehow know each other – I don’t want to be the rando if I DM them.

My own feeling is that if someone doesn’t know me and doesn’t spend half a minute to write me a sentence for why we should connect (I always do, when connecting with someone else I don’t know), then I’ll ignore the request. As LinkedIn says, such requests are indistinguishable, disingenuous, lacking creativity, or lazy. Am I missing something here?

Reply on Twitter, if you’re interested (sadly, spammers have led to us mostly turning off comments on this blog itself).

And if you did make a no-explanation invite and would like to explain why we truly should connect, great: email me, erich@acm.org (once upon a time I would not post my email address, but Gmail’s spam filter is quite effective). I currently see 35 pending invites, and you all look to be fine people (except you, Fred), so let me know why you want to connect.

Date: conference is May 5-7th 2020 (the venue was already booked for May 4th – I’ll let you puzzle out why). Call For Papers coming soon – due date likely in December (judging from past conferences).

Location: Industrial Light and Magic at the Presidio, San Francisco. Naty Hoffman did a lot of work to make this happen, and I’m super-excited that it will be there – pleasant buildings in a lovely location with cool memorabilia in a great city. And that last link is definitely worth clicking – Google Earth’s fun.

This is the I3D you don’t want to miss (especially once you submit your best work!).