Axel Paris
@axelparis.bsky.social
210 followers 250 following 19 posts
Research scientist at Adobe. PhD in Computer Graphics. Founding member of Newhead Studio. Interests: implicit surfaces, physics simulations, sustainability. Web: aparis69.github.io Game: hitmenparty.com => Opinions are my own. He/Him. Write in 🇨🇵 🇬🇧
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📜 New SIGGRAPH 2025 paper 🎉

❔How to compute bounding volumes for procedural Signed Distance Fields (SDFs)? This is not so trivial!

💡We propose a simple method called Sphere Carving. It extracts (convex) bounding volumes around SDFs, requires very few evaluations, and is GPU compatible.
Reposted by Axel Paris
I finally found the time and energy to make a new blog and write a couple of posts. This time I wrote about PBR content and game development principles. Both posts are quite different so hopefully people find something interesting on either one of them.

irradiance.ca/posts/
Posts
irradiance.ca
Reposted by Axel Paris
Computing the exact bijection of the optimal transport (OT) problem between very large point sets is completely untractable…

In our SIGGRAPH Asia 2025 paper: “BSP-OT: Sparse transport plans between discrete measures in log-linear time” we get one with typically 1% of error in a few seconds on CPU!
Reposted by Axel Paris
Les 1,8 millions de signatures de la pétition de Philippe de Villiers contre l'immigration sont complètement bidons, et je peux le prouver.

Mais il y a plus intéressant, ce qu'il y a derrière, à savoir une opération de l'empire Bolloré. Un thread 🧵⤵️ https://t.co/hHF2dUqi8Z
Un graphique affichant avec une courbe bleue l'évolution, à chaque minute, du nombre de signatures affiché sur le site, sur une période de nuit.

Une seconde courbe rouge est derrière, quasi identique, à un détail près : 4 pics de 50 signatures, qui correspondent aux moments où j'ai simulé des signatures.  C'est ce qui aurait dû apparaître si le compteur n'était pas truqué.
Reposted by Axel Paris
Eh ben celle-là, en termes de tartufferie, elle vient de faire péter le plafond de la Sixtine.
Reposted by Axel Paris
i don’t think people on bluesky understand the severity of this situation.

i woke up to literally hundreds of texts from friends and family thinking about either moving back home to india or applying to other countries for jobs. this includes me.
Those on an H1B cannot return to the US from tomorrow (Sunday) unless paying $100K. This is an out-of-the blue presidential action. We’ll see software engineers stranded abroad.

One easy to predict outcome: those on US visas will travel less… for work, for conferences etc.
Reposted by Axel Paris
En 1970, tous les banquiers d'Irlande ont fait grève. Ils pensaient que ça mettrait le pays à genoux. Raté. Après 6 mois, tout allait toujours bien, le PIB a même augmenté. Par contre quand les éboueurs de New York ont fait grève 10 jours, il a fallu déclarer l'urgence sanitaire.
Capture d'écran du tweet cité, à savoir : https://twitter.com/BFMTV/status/1966923514180510180
Reposted by Axel Paris
Ce week-end, j'ai pas mal donné mes tripes :/

Les papiers qui en sont sortis n'étaient pas les mieux, mais j'ai essayé de coucher un article de fond construit, sur comment fonctionne la dynamique audience/influenceurs d'un événement comme le ZEvent.

www.linkedin.com/posts/flef_z...
Cartographie du ZEvent, avec comme commentaires :
2 millions de viewers uniques
16 millions d'euros récoltés
Un résultat record grace à des communautés structurées.

En grand dans le texte : AUX RESULTATS INEGAUX
🚀The code for Lipschitz Pruning is now online thanks to @wbrbr.bsky.social🚀

🔗 github.com/wbrbr/Lipsch...

It's a simple Vulkan app useful for experiments. Also, the monument done by @elie-michel.bsky.social is released under a CC-BY license📄

(poke @mattkeeter.com I remember you asked!)
Sample image from the Lipschitz pruning released application
Reposted by Axel Paris
Vous avez sûrement déjà lu que la climatisation aggrave les canicules car l’air chaud rejeté à l’extérieur augmenterait la température des villes de 2 à 3°C.

Vérifions ce que disent vraiment les études scientifiques à ce sujet 🧑‍🔬

(lisez jusqu’au bout, car vous allez être 🤯🤯 à la fin)

#Thread
⬇️⬇️
Carte de Paris simulation îlot de chaleur
Reposted by Axel Paris
"why [would] anyone intelligent enough to be a scientist choose to be one [given] the unfavorable risk-to-reward ratio "?

One of the most intelligent people you could meet offers some answers: having ideas, watching them develop, and sharing them journals.biologists.com/jcs/article/...
Why would anyone want to be a scientist?
It is difficult to fathom why anyone intelligent enough to be a scientist would actually choose to be one. Doing good science requires the utmost exertion of body, mind and spirit, yet is consistently...
journals.biologists.com
Reposted by Axel Paris
Presenting this paper tomorrow morning at 9:30am, during the Lightning Fast Geometry session⚡
Come check it out if you can!
📜 New SIGGRAPH 2025 paper 🎉

❔How to compute bounding volumes for procedural Signed Distance Fields (SDFs)? This is not so trivial!

💡We propose a simple method called Sphere Carving. It extracts (convex) bounding volumes around SDFs, requires very few evaluations, and is GPU compatible.
Reposted by Axel Paris
“In Finland, the number of homeless people has fallen sharply. Those affected receive a small apartment & counselling with no preconditions. 4 out of 5 people affected make their way back into a stable life. And all this is CHEAPER than accepting homelessness.”

It costs a lot less to house people.
Finland ends homelessness and provides shelter for all in need - scoop.me
In Finland, the number of homeless people has fallen sharply. Why? The country applies the "Housing First" concept agains homelessness.
thebetter.news
Reposted by Axel Paris
Il y a 10 ans, il y avait d’énormes manifestations pour défendre la liberté d’expression. Aujourd’hui, critiquer le premier ministre vous envoie en garde à vue et stage de citoyenneté - à vos frais. bsky.app/profile/ludi...
Rappel des 3 phrases prononcées par cette femme à l'adresse du premier ministre:"Vous avez des comptes à rendre à tous les enfants qui se sont fait violer. Et aux gens qui n’ont pas un sou. Vous n’avez rien à faire ici M. Bayrou".
Pour ces 3 phrases:
- garde à vue
- stage de citoyenneté à ses frais
Reposted by Axel Paris
Par contre : plus de congés, la semaine de quatre jours et la taxation des riches - sans conditions sportives.
Reposted by Axel Paris
Ok, calmer, post-stream digested thoughts about GPT-5. I'll keep it short.

1. A lot of the presentation was vibes-based. "Is GPT-5 better at XYZ? This person said they feel it is. Ok, moving on..." I wonder how much this is because OpenAI think a lot of people use ChatGPT based on vibes already.
Different types of bound can be used - and it is even relatively simple to extract not only one, but multiple convex bounds around the object, with guarantees!
In practice, a usable bound can be extracted instantaneously for exact and quasi exact SDFs (50 queries). For more conservative functions where the SDF is a "bad" distance estimate (the distance is largely under estimated), then more iterations are required.
Sphere carving has the same general requirement than Sphere Tracing: as long as the function provides a conservative distance estimate (lower-bound), then the algorithm is guaranteed to converge to the shape.
Instead, Sphere carving iteratively approaches the surface by leveraging the SDF. Field function queries define a set of empty spheres, from which we extract intersection points that are used march towards the surface. The final point set has the property that the convex hull bounds the shape.
A "naive" approach for such task would be to densely sample the SDF & extract a bound using a bounding box or convex hull of the samples. This is however expensive (lots of queries) even on GPU, especially if the SDF is made of thousands of primitives.
📜 New SIGGRAPH 2025 paper 🎉

❔How to compute bounding volumes for procedural Signed Distance Fields (SDFs)? This is not so trivial!

💡We propose a simple method called Sphere Carving. It extracts (convex) bounding volumes around SDFs, requires very few evaluations, and is GPU compatible.
Reposted by Axel Paris
We're looking forward to presenting our talk at #SIGGRAPH2025 on Sunday Aug. 10 - 11AM, in West Building, Rooms 301-305!
Ever wondered how badly we're all addicted to buying new GPUs in graphics labs?

Come see our talk at #SIGGRAPH2025 to discuss how we can collectively move "Towards a sustainable use of GPUs in Graphics Research"

with @elie-michel.bsky.social @axelparis.bsky.social Octave Crespel and Felix Hähnlein
MOTIVATION
Graphical Processing Units (GPUs) are at the core of Computer Graphics research. These chips are critical for rendering images, processing geometric data, and training machine learning models. Yet, the production and disposal of GPUs emits CO2 and results in toxic e-waste [1].

METHOD
We surveyed 888 papers presented at SIGGRAPH (premier conference for computer graphics research), from 2018 to 2024, and systematically gathered GPU models cited in the text. 

We then contextualize the hardware reported in papers with publicly available data of consumers’ hardware [2, 3].

REFERENCES
[1] CRAWFORD, KATE. The Atlas of AI: Power, Politics, and the Planetary Costs of Artificial Intelligence. Yale University Press, 2021.
[2] STEAM. Steam Hardware Survey. https://store.steampowered.com/hwsurvey
[3] BLENDER. Blender Open Data. https://opendata.blender.org
Reposted by Axel Paris
🇬🇧 ✊ Virtuos France is on strike! After the success of Oblivion Remastered, management decided to reward the team with…A layoffs plan.

A strike has started on July 10th and our comrades need support. STJV set up a strike fund:

www.helloasso.com/as...
Caisse de grève Virtuos
Faire un don à Syndicat des Travailleurs et Travailleuses du Jeu Video - Caisse de grève Virtuos
www.helloasso.com