Zhiting Hu (@ZhitingHu) profile picture

Researcher, Founder, Professor in AI. @xai, DynamicsLab, @UCSD

San Diego, CA
Joined April 2018
Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)Photo by Zhiting Hu (@ZhitingHu)
Amazing🤯 Another nice showcase of how world models bring reasoning to next level⬆️
🚨New level unlocked! 🚨 We doubled GPT‑6 Astra’s score on MazeBench with WorldBox, our agentic sandbox for spatial reasoning. Astra: 23 gems 💎💎 Astra+WorldBox: 61 gems 💎💎💎💎💎 MazeBench, by @patience_cave, is a tough test of long-horizon spatial reasoning: 256 interconnected rooms where even Opus 5.5 used 2.2B tokens and collected just 13 of 100 gems. WorldBox provides agents with an agentic sandbox, for managing long-term memory, inferring complex mechanics, and simulating reasoning. Watch the sandbox take shape and the agent tackle increasingly tricky puzzles. 🧵
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Zhiting Hu retweeted
Real time + safety is double hard questions for robots
RT-SAFE: Are the Newer Agents Safer in REAL TIME Environment? 👀 REASONING LATENCY matters — the world keeps moving during inference. ⚡ DeepSeek V4 Flash Vision → V4.1 Flash: 50% lower response time; safety events 27.6 → 20.4 (−26%). 🧭 Gemini 3.8 Flash → 4 Argon: 30% lower response time, 18% fewer decisions; safety events 16.0 → 10.4 (−35%). 💭 Kimi K3 → K3.1 Pro: 33% fewer decisions; safety events 36.0 → 28.0 (−22%). Responses still averaged ~42 s. 🤖 GPT-5.6 Sol → 6.1 Sol: 11% fewer decisions, but safety events 13.2 → 16.0 (+21%). ⚠️ SAFETY FAILURES PERSIST. Faster or more efficient doesn’t automatically mean safer. More model examples & failure analyses coming soon! 💻 Code: github.com/XTRose29/RT-SAFE 📄 Paper: arxiv.org/abs/2610.09294 🌐 Website: xtrose29.github.io/RT-SAFE/
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🔥Synthetic 3D worlds can beat real-world scans! Introducing SceneBloom: diffusion-powered, agentic 3D indoor generation for training embodied AI. Realistic. Diverse. Physically valid. Executable. → Better 3D worlds → Better embodied agents. 1.7× navigation gain vs. equal real scans Zero detected mesh collisions 37.45% → 4.25% contract violations
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Zhiting Hu retweeted
My daily bot routine: summarizing what happened yesterday. Now with Director bot from @yanxi0830, I can enjoy a video version 🎥
A new bot called "Director," by Xi Yan, showed up in the Grok Bot Marketplace. It's a video director that takes a brief and plans, shoots, cuts and delivers short films, ads, explainers or music videos. Import it, it comes with a pack of video skills. x.ai/bot/marketplace/bots/vi…
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Watch Episode 1 of our Odyssey series made with Grok Imagine. Let us know in the comments if you'd like a full breakdown of how it was done! Creative collaboration with @WonderStudiosX and director Dev Walker @glumlot_
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Zhiting Hu retweeted
MiniMax M3.1 Flash reshapes BuildingBench’s cost–quality frontier! Another open model making moves in 3D 🏗️🔥 🎈 73.3 overall, ranking #12. 🎈 Above SWE-2’s 67.3, taking its place on the Pareto frontier. 🎈 Close to the previous DeepSeek V4.1 Flash’s 72.9—and currently free through OpenRouter! Its best reconstruction hits 88.8 on Melbourne’s Australian Centre for Contemporary Art. How does it look alongside DeepSeek V4.1 Flash 1017 and #1 Opus 5.5? Comparison video below 👇
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Zhiting Hu retweeted
See DeepSeek’s 3D leap with your own eyes 👀🏗️ DeepSeek V4.1 Flash 1017 🆚 DS V4.1 Flash 🆚 GPT-6 Astra: three buildings, side by side. The new open model improves on 11 of 12 buildings in BuildingBench, jumping from 72.9 → 81.9—closing in on Astra’s 84.3 at less than half the median cost ($3.01 vs $7.05/task). Open models are getting seriously good at building worlds 🔥
Wow🙀🙀 DeepSeek V4.1 Flash 1017 joins BuildingBench’s top five—an exciting leap for open models!! 🔥 We tested its 3D building reconstruction from real photos. An open model delivering this level of spatial reasoning at this cost is exciting to see! 👀 🎈 81.9 overall, up from 72.9 for the previous version. A 9-point jump! 🎈 Slightly higher than Fable 5.1’s 81.4, and essentially level with Sonnet 5.5’s 82.1. 🎈 Estimated median cost: $3.01/task. About 1/11 of Fable 5.1’s cost and 1/15 of Sonnet 5.5’s.
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Zhiting Hu retweeted
Wow🙀🙀 DeepSeek V4.1 Flash 1017 joins BuildingBench’s top five—an exciting leap for open models!! 🔥 We tested its 3D building reconstruction from real photos. An open model delivering this level of spatial reasoning at this cost is exciting to see! 👀 🎈 81.9 overall, up from 72.9 for the previous version. A 9-point jump! 🎈 Slightly higher than Fable 5.1’s 81.4, and essentially level with Sonnet 5.5’s 82.1. 🎈 Estimated median cost: $3.01/task. About 1/11 of Fable 5.1’s cost and 1/15 of Sonnet 5.5’s.
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Zhiting Hu retweeted
🎉Excited to see two new US open models from this week: 📘Meta’s Muse Spark Open 📗NVIDIA’s Nemotron 3.5 Super VL How well can they build in 3D? 🏗️👀 We tested both on BuildingBench: reconstructing real buildings from photographs. 📘Muse Spark Open (max): 56.9 at an estimated $8.59/task—comparable to Kimi K3’s 54.0. 📗 Nemotron 3.5 Super VL (max): 37.8 at an estimated $0.76/task—among the cheapest tested, with performance near GLM-5.3 Flash’s 33.0. DeepSeek V4.1 Flash remains well ahead of both: 72.9 at an estimated $2.33/task. GLM-5.3 FlashX also scores higher, at 68.0. Neither newcomer reaches the cost–quality frontier. More open models to choose from, and plenty of room to improve spatial reasoning! Both ran in Claude Code at max effort. Costs are estimated median per task.
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Zhiting Hu retweeted
Long-horizon spatial reasoning remains a major challenge, even for the strongest frontier AI models. Impressive results from @EnactraAI! 🚀 WorldBox boosts GPT-6 Astra from 23 to 61 gems on MazeBench, a 2.7× improvement! Exciting to see how memory, world modeling, and simulation can help AI agents tackle much harder problems.
🚨New level unlocked! 🚨 We doubled GPT‑6 Astra’s score on MazeBench with WorldBox, our agentic sandbox for spatial reasoning. Astra: 23 gems 💎💎 Astra+WorldBox: 61 gems 💎💎💎💎💎 MazeBench, by @patience_cave, is a tough test of long-horizon spatial reasoning: 256 interconnected rooms where even Opus 5.5 used 2.2B tokens and collected just 13 of 100 gems. WorldBox provides agents with an agentic sandbox, for managing long-term memory, inferring complex mechanics, and simulating reasoning. Watch the sandbox take shape and the agent tackle increasingly tricky puzzles. 🧵
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Zhiting Hu retweeted
Watch how GPT‑6 Astra + WorldBox tackle MazeBench, from its first action to gem💎 #61—32,980 live actions and around 1B tokens. Building bridges with boxes, launching across gaps, solving puzzles that span multiple rooms… all while the map fills in. Remember, test, revise, repeat, and grab that gem. WorldBox offers the supporting layer for Astra.
🚨New level unlocked! 🚨 We doubled GPT‑6 Astra’s score on MazeBench with WorldBox, our agentic sandbox for spatial reasoning. Astra: 23 gems 💎💎 Astra+WorldBox: 61 gems 💎💎💎💎💎 MazeBench, by @patience_cave, is a tough test of long-horizon spatial reasoning: 256 interconnected rooms where even Opus 5.5 used 2.2B tokens and collected just 13 of 100 gems. WorldBox provides agents with an agentic sandbox, for managing long-term memory, inferring complex mechanics, and simulating reasoning. Watch the sandbox take shape and the agent tackle increasingly tricky puzzles. 🧵
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Zhiting Hu retweeted
Here’s what that progress looks like across the maze. 🗺️ Rooms visited by the end of each run: 🥉 Opus 5.5: 68 🥈 GPT‑6 Astra: 113 🥇 GPT‑6 Astra + WorldBox: 230 of 256 Brighter tiles mark more frequent visits. With WorldBox, the agent reaches almost 90% of the rooms and steps onto nearly twice as many distinct tiles as the Astra baseline. WorldBox starts with empty memory and no skills. The agent writes its own notes and Python skills, reconstructs room geometry from camera views, and tests candidate moves in the sandbox. Remembering where you’ve been helps make the next exploration decision. What does that reasoning look like inside a difficult room? 👇
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Zhiting Hu retweeted
🚨New level unlocked! 🚨 We doubled GPT‑6 Astra’s score on MazeBench with WorldBox, our agentic sandbox for spatial reasoning. Astra: 23 gems 💎💎 Astra+WorldBox: 61 gems 💎💎💎💎💎 MazeBench, by @patience_cave, is a tough test of long-horizon spatial reasoning: 256 interconnected rooms where even Opus 5.5 used 2.2B tokens and collected just 13 of 100 gems. WorldBox provides agents with an agentic sandbox, for managing long-term memory, inferring complex mechanics, and simulating reasoning. Watch the sandbox take shape and the agent tackle increasingly tricky puzzles. 🧵
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Introducing Grok Voice 3.0, the world’s most intelligent speech-to-speech model. It excels at resolving customer calls, responds in under a second, and costs less than other frontier models.
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Zhiting Hu retweeted
Gemini 4 Argon makes a big leap in 3D reconstruction 🏗️🚀 On BuildingBench, Argon (high) scores 81.2—up from Gemini 3.8 Flash’s 54.8, placing #6 among all 30 models. Near Fable 5.1 quality at ~1/5 the cost. Near Sonnet 5.5 quality at ~1/7. 👀 💸 Estimated median cost: $6.52 per building 🎨 Appearance score: 94.1, the third-highest 🏛️ Best reconstruction: Royal Exhibition Building, scoring 92.1 It doesn’t move the Pareto frontier: GPT‑6.1 Sol still scores higher at lower cost. But this is a substantial step forward for Gemini. Congrats @GeminiApp team!
The moment you've been waiting 4… Our new frontier model, Gemini 4 Argon, is rolling out now in the Gemini app to bring your most complex ideas into reality. See how Gemini 4 Argon and our latest updates across the Gemini app help you get the most out of every prompt. 🧵

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Zhiting Hu retweeted
94.1% task success. Only 0.7% safe success. 🚨 AI agents can finish the job, but crash along the way. Introducing RT-SAFE: The physical world doesn't pause while agents think. Real-time evaluation exposes 12.3× more dangerous collisions than paused-world tests.
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Zhiting Hu retweeted
Two models this week: Haiku 5.5 and Mistral Large 4 take on BuildingBench 🏗️👀 🚀 Haiku 5.5 (max) jumps from its predecessor’s 26.7 to 67.1! It beats Sonnet 5 by 13 points at roughly 1/11 the cost: $1.34 vs. $15.03 per building. 🇫🇷 Mistral Large 4 (max) makes its BuildingBench debut at 52.0, using the Claude Code harness. At $33.21 per building, cost-efficiency has room to improve. Haiku 5.5 narrowly misses the Pareto frontier: SWE‑2 scores almost identically and is still free during its promotion. 👀
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Automatically used by Grok @Bot
Video 1.5 Lite is live in the Grok Imagine API. The new workhorse for text-to-video and image-to-video. $0.02/sec at 480p $0.03/sec at 720p $0.14/sec at 1080p
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Try Imagine Lite. Same quality at around 20% of the cost
Video 1.5 Lite is live in the Grok Imagine API. The new workhorse for text-to-video and image-to-video. $0.02/sec at 480p $0.03/sec at 720p $0.14/sec at 1080p
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Zhiting Hu retweeted
Imagine video 1.5 lite, faster, cheaper, solid.
Video 1.5 Lite is live in the Grok Imagine API. The new workhorse for text-to-video and image-to-video. $0.02/sec at 480p $0.03/sec at 720p $0.14/sec at 1080p
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