iiinova — where your digital self keeps evolving

Keenan Crane @keenancrane.bsky.social · 19/07/2026

Going to the #SIGGRAPH2026 Fast Forward Session? Here's a much better way to keep track of talks you want to see: keenancrane.github.io/siggraph-pap... Tap the talks you want to go to, then share (as Markdown) or save directly to your calendar. Also flags conflicting times. ⚠️

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Keenan Crane @keenancrane.bsky.social · 18/07/2026

#SIGGRAPH2026 attendees: I made a better webpage for the Technical Papers schedule. You can search, filter on keywords, and scroll through linearly (rather than opening a zillion folds) + add to calendar: keenancrane.github.io/siggraph-pap... Can also download a flat JSON & CSV of talks & times.

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Keenan Crane @keenancrane.bsky.social · 02/06/2026

Giving a talk in the @Stanford SCIEN seminar this Wednesday (1/3) at 4:30pm: scien.stanford.edu/index.php/ev... The topic is “normal coordinates”: a shape representation little-used outside of mathematics—but which turns out to have nice applications in geometry processing & learning.

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Keenan Crane @keenancrane.bsky.social · 04/05/2026

The wonderful Nicole Feng, defending her PhD thesis on generalized distances & winding numbers. So proud of her, and very excited about all the places she will go. nzfeng.github.io (Also that text outline shaded by the surface is some galaxy brain diagramming. 🤯🧠🌌)

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Keenan Crane @keenancrane.bsky.social · 18/01/2026

The best time to plant a tree is 20 years ago. The second best time is three hours before the paper deadline.

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Keenan Crane @keenancrane.bsky.social · 29/10/2025

Fantastic video from @SciShow about our work that turns any shape into fair dice: youtu.be/-gp7AbYD9NI?... Get all the details on Hossein Baktash’s page here: hbaktash.github.io

youtu.be

How to Make Fair DnD Dice from ANY Shape

YouTube video by SciShow

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Keenan Crane @keenancrane.bsky.social · 25/09/2025

“Fair dice” might make you think of perfect cubes with equal frequencies (say, 1/6 on all sides) 🎲 But “fair” really just means you get the frequencies you expect (say, 1/4, 1/4 & 1/2) We can now design fair dice with any frequencies—and any shape! 🐉 hbaktash.github.io/projects/put...

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Keenan Crane @keenancrane.bsky.social · 24/09/2025

Nicely produced clip by Matt Wein and Marylee Williams about our recent dice design project at @scsatcmu.bsky.social and @adobe.com youtube.com/shorts/jD0ag... 🎲 🎥 🐉 🪙

youtube.com

Rethinking Fair Dice

YouTube video by CMU School of Computer Science

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Keenan Crane @keenancrane.bsky.social · 11/09/2025

I got tired of mashing together tools to write long threads with 𝐫𝐢𝐜𝐡 𝑓𝑜𝑟𝑚𝑎𝑡𝑡𝑖𝑛𝑔 and ℳα†ℏ—so I wrote La𝑇𝑤𝑒𝑒𝑡! It converts Markdown and LaTeX to Unicode that can be used in “tweets”, and automatically splits long threads. Try it out! keenancrane.github.io/LaTweet/

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Keenan Crane @keenancrane.bsky.social · 06/09/2025

“Everyone knows” what an autoencoder is… but there's an important complementary picture missing from most introductory material. In short: we emphasize how autoencoders are implemented—but not always what they represent (and some of the implications of that representation).🧵

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Keenan Crane @keenancrane.bsky.social · 29/08/2025

I can't* fathom why the top picture, and not the bottom picture, is the standard diagram for an autoencoder. The whole idea of an autoencoder is that you complete a round trip and seek cycle consistency—why lay out the network linearly?

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Keenan Crane @keenancrane.bsky.social · 12/08/2025

I don't have a strong opinion about whether video models “understand the world.” But I do think the first bar should be checking whether you can recover consistent geometry from video—not whether it makes accurate predictions of physics.

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Reposted by Keenan Crane

Bruno Levy @brunolevy01.bsky.social · 19/07/2025

#geogram + #graphite + #blender Python scripting = robust CSG directly available in Blender ! Everything is a numpy array.

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Keenan Crane @keenancrane.bsky.social · 02/07/2025

Awesome work by two awesome former students. 🦖🏁

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Keenan Crane @keenancrane.bsky.social · 29/06/2025

Working on a Walk on Spheres tutorial for #SIGGRAPH2025, and love the ads I'm getting served. 😂 Stay tuned for more…👣

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Keenan Crane @keenancrane.bsky.social · 28/06/2025

Quick “teaser” for a fun #SIGGRAPH2025 project, led by Hossein Baktash, on optimizing a shape to have the desired rolling statistics. Basically we can turn arbitrary objects into fair dice, or make dice which capture the statistics of other objects—like several coin flips.

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Keenan Crane @keenancrane.bsky.social · 26/06/2025

Making good on this promise—in the fastest turnaround time ever—my collaborator Etienne Corman has just posted MATLAB code for #RectangularSurfaceParameterization here: github.com/etcorman/Rec... (C++ version is still in the works…)

A teaser image for Rectangular Surface Parameterization, with large letters "RSP" meshed in blue, surrounded by a collection of yellow rectangular quad meshes generated by the RSP algorithm.

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Keenan Crane @keenancrane.bsky.social · 26/06/2025

Meshes with 90° angles are super useful, providing asymptotically faster convergence for finite element simulation, and optimal shape approximation (when aligned with curvature). Amazingly, no past quad meshing method could guarantee 90° angles under refinement—until now. #RSP

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Keenan Crane @keenancrane.bsky.social · 23/06/2025

Very happy that Jiří Minarčík will join our research group at @cmu.edu, the Geometry Collective, as a Fulbright visiting scholar! 🥳 Jiří is a world expert in space curves, and one of the core contributors to Penrose (penrose.cs.cmu.edu). Check out his beautiful work here: minarcik.com

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Keenan Crane @keenancrane.bsky.social · 20/06/2025

Folks in the #SIGGRAPH community: You may or may not be aware of the controversy around the next #SIGGRAPHAsia location, summarized here www.cs.toronto.edu/~jacobson/we... If you're concerned consider signing this letter docs.google.com/document/d/1... via this form docs.google.com/forms/d/e/1F...

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Keenan Crane @keenancrane.bsky.social · 20/06/2025

Very happy to receive a SIGGRAPH 2025 Best Paper Award (Honorable Mention) for our RSP algorithm, which dices surfaces into near-perfect rectangles. Such meshes are useful for everything from retopology, to microfluidic simulation, to textile design, to architectural geometry.

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Keenan Crane @keenancrane.bsky.social · 15/06/2025

Shout out today to parents, grandparents, aunts, uncles, or anyone else who helps raise a kid. It didn’t really click until I was a dad: without parents, human civilization ends. Only with good parents does the future look bright. So, give a nod to anyone putting in the work.

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Reposted by Keenan Crane

Bruno Levy @brunolevy01.bsky.social · 13/06/2025

Mesh intersections is hard ! Three years of agonizing pain summarized in my article that just got accepted to ACM Transactions on Graphics dl.acm.org/doi/10.1145/... The implementation and the expansion-based arithmetic kernel are available in geogram: github.com/BrunoLevy/ge...

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Keenan Crane @keenancrane.bsky.social · 13/06/2025

Hey @nervousjesse.bsky.social @nervousjessica.bsky.social, how come you don't sell a waste basket (or recycling bin) in your shop? Would be a welcome alternative to conventional wicker or wire baskets. (Maybe modeled after lysosomes or peroxisomes?)

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Keenan Crane @keenancrane.bsky.social · 07/06/2025

Generative art circa 2004. Inspired by Piet Mondrian and rendered in acrylic. (Currently on display at my grandmother’s house)

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Keenan Crane @keenancrane.bsky.social · 30/05/2025

More in-depth article, on Ars Technica, about our recent dice design/rigid body project led by Hossein Baktash at CMU: arstechnica.com/science/2025... You can find the full paper and 3D printable STL files on Hossein's webpage here: hbaktash.github.io

arstechnica.com

Your next gaming dice could be shaped like a dragon or armadillo

Statistically, “the real behavior of a rolling object is largely a function of its geometry.”…

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Reposted by Keenan Crane

Golan Levin @golan.bsky.social · 29/05/2025

Terrific new work in designing fair dice with arbitrary shapes, by Hossein Baktash at CMU: • www.newscientist.com/article/2482... • hbaktash.github.io/files/rollin...

hbaktash.github.io

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Keenan Crane @keenancrane.bsky.social · 29/05/2025

Anyone interested in 3D printing some funky dice—like a "fair dragon" which can land in three different ways, or a single die equivalent to to 2D6? We've now put printable STL files online: www.cs.cmu.edu/~kmcrane/Pro... More info here: hbaktash.github.io

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Keenan Crane @keenancrane.bsky.social · 29/05/2025

Great writeup by @stokel.bsky.social about our #SIGGRAPH paper on dice design (and rigid body analysis), led by my awesome PhD student Hossein Baktash: hbaktash.github.io

hbaktash.github.io

About me

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Keenan Crane @keenancrane.bsky.social · 21/05/2025

Fun new paper at #SIGGRAPH2025: What if instead of two 6-sided dice, you could roll a single "funky-shaped" die that gives the same statistics (e.g, 7 is twice as likely as 4 or 10). Or make fair dice in any shape—e.g., dragons rather than cubes? That's exactly what we do! 1/n

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Keenan Crane @keenancrane.bsky.social · 13/05/2025

Huge congratulations to my former PhD student Rohan Sawhney for winning the @acmsiggraph.bsky.social Outstanding Doctoral Dissertation Award! 🥳 Rohan's thesis develops a whole new class of Monte Carlo methods for solving physical equations, without needing to break the world up into a mesh.

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Keenan Crane @keenancrane.bsky.social · 09/05/2025

If you're a prospective PhD student interested in geometry, topology, and applications in geometric/visual computing, check out the incredible Mark Gillespie, who is joining the faculty at graphics.cs.utah.edu — and looking for students! markjgillespie.com

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Keenan Crane @keenancrane.bsky.social · 02/05/2025

Jensen's inequality gives the difference between the average value of a convex function φ, and its value at the center, where both “average” and “center” are defined in terms of some distribution p_X. When the function φ is flat, or the distribution is narrow, they agree.

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Keenan Crane @keenancrane.bsky.social · 01/05/2025

After trying several broken repos/scripts, I made a Python script for rendering #ShaderToy shaders to antialiased video (or rather, image sequences): github.com/keenancrane/... (This one will surely be broken too someday, but for now it works nicely 😛)

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Keenan Crane @keenancrane.bsky.social · 19/04/2025

I looked at this image many times as a kid, saw it at the Met, eventually met mathematician Tom Banchoff, who told stories of his encounters with Dalí & their discussions about the 4th dimension. Only today did I realize it’s Christ on the hypercube. m.youtube.com/watch?v=IiXc...

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Keenan Crane @keenancrane.bsky.social · 18/04/2025

I'll let you in on one of my deep diagramming secrets: When I see a “square”, I replace it with a square. When I see a “cube”, I replace it with a cube. It's easy to forget where these words come from. The only mistake we made as a species is not calling numbers “segments.”

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Keenan Crane @keenancrane.bsky.social · 18/04/2025

Here's a nice "proof without words": The sum of the squares of several positive values can never be bigger than the square of their sum. This picture helps make sense of how ℓ₁ and ℓ₂ norms regularize and sparsify solutions (resp.). [1/n]

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Keenan Crane @keenancrane.bsky.social · 17/04/2025

We have entered an era where it pays to have decent handwriting. [This was truly the only prompt; I did not edit the output.] #o4

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Keenan Crane @keenancrane.bsky.social · 07/04/2025

We often use discretization to approximate continuous laws of physics, but it also goes the other way: You can use continuous equations to approximate the behavior of discrete systems! Here we'll see how electrical circuits can be modeled using the Laplace equation Δφ=0. [1/n]

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Reposted by Keenan Crane

Nicholas Sharp @nmwsharp.bsky.social · 01/04/2025

The Symposium on Geometry Processing is an amazing venue for geometry research: meshes, point clouds, neural fields, 3D ML, etc. Reviews are quick and high-quality. The deadline is in ~10 days. Consider submitting your work, I'm planning to submit! sgp2025.my.canva.site/submit-page-...

sgp2025.my.canva.site

SGP 2025 - Submit page

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Keenan Crane @keenancrane.bsky.social · 28/03/2025

Stupid #Keynote trick: if you want the math font to match the text font, write expressions like \𝚝𝚎𝚡𝚝{𝚞}_\𝚝𝚎𝚡𝚝{𝚒} rather than just 𝚞_𝚒 when inserting equations. [Wish this were just the default behavior…]

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Keenan Crane @keenancrane.bsky.social · 27/03/2025

OpenAI's new 4o image generation is pretty amazing. It also fails on some utterly basic tasks. Maybe a good metaphor for how easily we can be misled by algorithms based largely on fitting empirical data (i.e., machine learning) rather than deductive reasoning. penrose.cs.cmu.edu

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Reposted by Keenan Crane

Mirela Ben Chen @mirelaben.bsky.social · 25/03/2025

As the spring semester is starting, this is the bi-yearly reminder of the collections of courses on geometry processing available here: mirelab6.wixsite.com/dgpslides. Ping me if you teach geometry processing and want your course added.

mirelab6.wixsite.com

Home | 3D Geometry Processing Courses and Seminars

3D GEOMETRY PROCESSING COURSES AND SEMINARS

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Keenan Crane @keenancrane.bsky.social · 12/03/2025

One of the absolute best students I've ever had (star @Caltech grad and @CarnegieMellon PhD in Computer Science) just had faculty interviews canceled because universities are on a hiring freeze, due to uncertainty about funding. Not a great move for technological supremacy💀💻🇺🇸

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Keenan Crane @keenancrane.bsky.social · 06/03/2025

Poorly worded #SIGGRAPH author instructions. If you have negative scores (individual or average), 𝗴𝗼 𝗮𝗵𝗲𝗮𝗱 𝗮𝗻𝗱 𝘄𝗿𝗶𝘁𝗲 𝗮 𝘀𝘁𝗿𝗼𝗻𝗴 𝗿𝗲𝗯𝘂𝘁𝘁𝗮𝗹! Negative scores are not a mark of death. Plenty misunderstandings get cleared up in the rebuttal; plenty initially low-score papers are ultimately accepted.

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Keenan Crane @keenancrane.bsky.social · 19/02/2025

This might look like an anisotropic texture filtering benchmark, but actually it’s just Detroit.

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Keenan Crane @keenancrane.bsky.social · 12/02/2025

I don't know who needs to hear this but: "SDF" has, for some, become a catch-all term that actually means "a function that tells you if you're inside/outside a shape, and a number that roughly indicates how far." A true signed *distance* function really gives you *distance.*

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Keenan Crane @keenancrane.bsky.social · 11/02/2025

After many years of giving talks, I no longer get nervous. Instead, I'm now nervous when my students give talks! Fortunately, they do an amazing job. Here's Mark Gillespie giving an extended talk on a new *harmonic* surface representation: www.youtube.com/watch?v=9h13...

youtube.com

Ray Tracing Harmonic Functions (Extended Talk)

YouTube video by Mark Gillespie

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Keenan Crane @keenancrane.bsky.social · 03/01/2025

This is what people mean when they talk about "readable code," right? (This is in fact a valid—and useful—line of #Mathematica code…)

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Keenan Crane @keenancrane.bsky.social · 31/12/2024

It's been debated, considered, and ultimately rejected several times over the years. But as a dissenting voice, I will continue to say: The SIGGRAPH deadline should really come *before* the holidays. (Yes, I'm aware of all the logistical hurdles and counter-arguments…)

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