From 3D/4D Scene Understanding to Semantic-metric World Models
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updated Jul 24, 2026
📜 A curated archive of World Intelligence research — from spatial perception to physical interaction and world models.
perceive → reconstruct → generate → act → predict/simulate
oh-my-spatial-intelligence → oh-my-world-intelligence. Spatial intelligence (categories 1–5) knows the world's current state; Physical AI (category 6) acts on it; World Models (category 7) predict its next state.World intelligence research is scattered across communities — neural rendering, 3D geometry, perception, robotics, and the rapidly exploding world-model literature. This repository aims to:
Every paper is placed by a single question: "What is the PRIMARY optimization objective?"
| Optimization target | Category |
|---|---|
| Photometric consistency | 1. Rendering & Representation |
| Correspondence & global alignment | 2. Geometry & Structure |
| Static 3D generative prior | 3. Generative 3D |
| Semantics & feature extraction | 4. Perception & Understanding |
| SE(3) pose registration | 5. 6D Pose Estimation |
| Physical properties, action & interaction | 6. Physical AI & Interaction |
| Prediction of unobserved future states | 7. World Models |
Boundary rules:
Ambiguous cases are settled by precedent — see the Boundary-Case FAQ.
How do we represent the world so it can be rendered? — Photometric Consistency & Neural Rendering
Optimized for how closely a rendering matches input images, not for geometric accuracy: a lumpy mesh is fine if the rendered image looks right. From the world-model perspective, this line owns the explicit-3D side of the "which space should hold world state — pixels, latents, or explicit 3D?" debate.
📦 Archived
🔭 Also notable: NeRF · 3D Gaussian Splatting · Instant-NGP
How do we recover shape? — Correspondence, Global Alignment & Test-Time Training
Maps pixels directly to 3D coordinates and optimizes metric accuracy of the recovered structure. Time-axis papers stay here as long as they reconstruct observed intervals (boundary rule 1). The test-time-training memory mechanisms of TTT3R/LoGeR connect directly to online adaptation and state maintenance in world models (cf. AdaJEPA in 7-1).
📦 Archived
🔭 Also notable: DUSt3R · MVSNet · COLMAP
How do we imagine what we cannot see? — Hallucination & Learned Priors
Fills unobserved regions by imagining from learned data distributions rather than computing them. Static 3D generation stays here even when autoregressive (boundary rule 2) — GaussianGPT is flagged as a promotion candidate to category 7 the moment action conditioning is added.
📦 Archived
🔭 Also notable: DreamFusion · Magic3D
What is it, and what does it mean? — Semantics & Feature Extraction
Identifies semantic classes, parts, and features beyond geometry. From the world-model perspective this category is the upstream supplier of observation encoders — the quality of a V-JEPA-style world model is bounded by its encoder.
00_UniversalEncoders/)Task-agnostic visual representations via self-supervised pretraining or multi-teacher distillation.
point-cloud-analysis/)Backbone networks learning high-dimensional features for classification and segmentation of point clouds.
Hierarchical relations and attributes over 3D maps. Also notable: Open-Vocabulary 3D Scene Graphs · Hydra · S-Graphs
03_OpenWorld_Segmentation/)Transfers SAM-family 2D segmentation knowledge to 3D (Gaussians) and video for promptable segmentation of arbitrary objects.
Where is the object, and in what pose? — Pose Matching & Registration
Estimates the SE(3) transform $(R, t)$ between an observation and a known reference under a rigid-body assumption. Frame-to-frame pose tracking is a time-series state estimate that feeds manipulation (6) and world-model state initialization (7).
📦 Archived
🔭 Also notable: MegaPose · PVNet
How do we act on the world? — Action-Oriented Perception & Physics
Beyond seeing: infer the physical/functional properties needed for interaction, build the physics substrate world models run on, or output actions directly. Boundary with 7: learn a predictive model → 7; build or touch the world → 6 (boundary rule 3).
Note: the former sub-category 6-1 Dynamic 4D Reconstruction was dissolved — applying the placement question consistently, observed-interval dynamic reconstruction (4DGS, D-NeRF, UFO-4D) belongs to category 2 and future-dynamics prediction to category 7.
02_Physics-based/)Inverse-physics estimation of latent parameters (mass, friction, elasticity, articulation) and generation of simulation-ready assets.
Also notable: PAC-NeRF · Diff-Physics · PhyGround (physics-fidelity benchmark)
Maps functional possibilities — where and how an object can be manipulated — onto 3D space. Also notable: Contact-GraspNet · Affordance Diffusion · Where2Act
04_PolicyLearning/)Visuomotor policies and action representations: papers whose objective is the policy itself, without learning a world model.
Also notable: Diffusion Policy · ACT · OpenVLA · π0
How do we predict the world's next state? — Future-State Prediction & Action-Conditioned Rollout
Papers whose primary objective is learning the transition function $p(s_{t+1} \mid s_t, a_t)$ — predicting states not yet observed, whatever space the state lives in. Sub-categories follow the one mutually exclusive axis the community actually divides along: the representation space of the rollout. Function (Renderer/Simulator/Planner), conditioning, domain, and physics grounding are multi-valued attributes handled as tags, not directories.
01_LatentPrediction/)Future rollouts happen in latent space — no pixels are generated during planning or imagination, which is why latent planners are fast (V-JEPA 2 plans ~15× faster than pixel-generative baselines). Includes both reconstruction-free JEPA models and RSSM/Dreamer models with auxiliary decoders: the criterion is where the rollout lives, not whether a reconstruction loss exists.
Also notable: DINO-world · Dreamer 4
02_GenerativeVideo/)Future frames are generated directly by diffusion/autoregressive transformers. Visual fidelity is the strength; action conditioning is the practical line between a video generator and a world model.
Also notable: Sora 2 · Genie 3 · NVIDIA Cosmos · GAIA-2/GAIA-3 · Vista · PAN
Future/unobserved states output as explicit 3D structure (Gaussians, meshes) maintaining a persistent, physically explorable world state. Also notable: Marble (World Labs)
04_MultimodalReasoning/)World state modeled in interleaved verbal + visual representations: the world model lives inside the chain-of-thought of an LLM/UMM, with visual generation serving as world simulation for reasoning.
Also notable: PAN · Cosmos 3 (Reason) · ThinkMorph
Placement case law — every ruling applies the single question "what is the PRIMARY optimization objective?".
| Case | Ruling | Rationale |
|---|---|---|
| UFO-4D is 4D — why not 7? | 2 | Reconstructs + interpolates observed frames; no future rollout (rule 1) |
| GaussianGPT is autoregressive — why not 7? | 3 | Autoregressive rollout but static scene generation, no time dynamics or actions (rule 2); promotion candidate if actions are added |
| PhysForge — why not 7? | 6-2 | Generates physics-attached sim-ready assets; does not predict futures (rule 3) |
| Physical Representation Learning — why not 6-2? | 7-1 | Latent-space future prediction (JEPA) is the training objective |
| PhyWorld-style physics-aligned video generation? | 7-2 + physics tag | Objective is physics-aligned future video generation; pure fidelity benchmarks/evaluation go to 6-2 |
| AdaJEPA-style TTT of world models? | 7-1 | The object being adapted is the latent world model itself; the TTT mechanism cross-references Test3R/TTT3R (category 2) |
| Reasoning Visual World — why not 7-2? | 7-4 | Not video rollout: world modeling inside interleaved visual-verbal CoT — a multimodal representation space |
| Joint policy + world-model training (UWM-style)? | 7-2 + Planner tag | The joint loss weights future-observation prediction equally — learning, not consuming (rule 3); a policy paper consuming a frozen world model goes to 6 |
| DreamerV3 has a reconstruction decoder — why 7-1? | 7-1 | The 7-1 criterion is the rollout space, not the presence of a reconstruction loss: RSSM imagination is fully latent; the decoder is an auxiliary representation signal |
| I-JEPA is "JEPA" — why not 7-1? | 4-0 | JEPA is an architecture (embedding-space prediction), not a world model per se. Spatial masks of a static image → representation learning (4-0); temporal future states → world model (7-1) |
Category-7 papers carry these tags in their project README / study note (multi-valued attributes → tags, not directories):
| Tag axis | Values |
|---|---|
| Function (Fei-Fei Li taxonomy) | Renderer / Simulator / Planner |
| Conditioning | action / text / multimodal |
| Domain | driving / robotics / game / general |
| Physics grounding | implicit (data statistics) / explicit (physics alignment, simulator coupling) |
Category 7's sub-structure aligns with the 2025–2026 community-standard frameworks (kept as references, not directories):
<Category>/<NN_SubCategory>/<YYYY_PaperName>/
├── YYYY_PaperName.pdf # the paper itself
├── README.md # summary, links, BibTeX, placement notes
├── study_note.md # standardized concept mind-map (via /paper-to-note)
└── <implementation>/ # official or reference code, self-contained env
YYYY_PaperName/ by publication year. Planned sub-directories are created only when their first paper arrives — no empty scaffolding.Perception/point-cloud-analysis/ (historical, no numeric prefix) and Perception/00_UniversalEncoders/2026_PerceptionEncoder/ (published 2025; rename pending).YYYY_PaperName/ under the correct (sub-)category directory.README.md with summary, links, and BibTeX; category-7 papers also record their tags.study_note.md (concept mind-map format).CLAUDE.md in the same commit.33 commits
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From 3D/4D Scene Understanding to Semantic-metric World Models
Jupyter Notebook
0
33 commits
updated Jul 24, 2026
📜 A curated archive of World Intelligence research — from spatial perception to physical interaction and world models.
perceive → reconstruct → generate → act → predict/simulate
oh-my-spatial-intelligence → oh-my-world-intelligence. Spatial intelligence (categories 1–5) knows the world's current state; Physical AI (category 6) acts on it; World Models (category 7) predict its next state.World intelligence research is scattered across communities — neural rendering, 3D geometry, perception, robotics, and the rapidly exploding world-model literature. This repository aims to:
Every paper is placed by a single question: "What is the PRIMARY optimization objective?"
| Optimization target | Category |
|---|---|
| Photometric consistency | 1. Rendering & Representation |
| Correspondence & global alignment | 2. Geometry & Structure |
| Static 3D generative prior | 3. Generative 3D |
| Semantics & feature extraction | 4. Perception & Understanding |
| SE(3) pose registration | 5. 6D Pose Estimation |
| Physical properties, action & interaction | 6. Physical AI & Interaction |
| Prediction of unobserved future states | 7. World Models |
Boundary rules:
Ambiguous cases are settled by precedent — see the Boundary-Case FAQ.
How do we represent the world so it can be rendered? — Photometric Consistency & Neural Rendering
Optimized for how closely a rendering matches input images, not for geometric accuracy: a lumpy mesh is fine if the rendered image looks right. From the world-model perspective, this line owns the explicit-3D side of the "which space should hold world state — pixels, latents, or explicit 3D?" debate.
📦 Archived
🔭 Also notable: NeRF · 3D Gaussian Splatting · Instant-NGP
How do we recover shape? — Correspondence, Global Alignment & Test-Time Training
Maps pixels directly to 3D coordinates and optimizes metric accuracy of the recovered structure. Time-axis papers stay here as long as they reconstruct observed intervals (boundary rule 1). The test-time-training memory mechanisms of TTT3R/LoGeR connect directly to online adaptation and state maintenance in world models (cf. AdaJEPA in 7-1).
📦 Archived
🔭 Also notable: DUSt3R · MVSNet · COLMAP
How do we imagine what we cannot see? — Hallucination & Learned Priors
Fills unobserved regions by imagining from learned data distributions rather than computing them. Static 3D generation stays here even when autoregressive (boundary rule 2) — GaussianGPT is flagged as a promotion candidate to category 7 the moment action conditioning is added.
📦 Archived
🔭 Also notable: DreamFusion · Magic3D
What is it, and what does it mean? — Semantics & Feature Extraction
Identifies semantic classes, parts, and features beyond geometry. From the world-model perspective this category is the upstream supplier of observation encoders — the quality of a V-JEPA-style world model is bounded by its encoder.
00_UniversalEncoders/)Task-agnostic visual representations via self-supervised pretraining or multi-teacher distillation.
point-cloud-analysis/)Backbone networks learning high-dimensional features for classification and segmentation of point clouds.
Hierarchical relations and attributes over 3D maps. Also notable: Open-Vocabulary 3D Scene Graphs · Hydra · S-Graphs
03_OpenWorld_Segmentation/)Transfers SAM-family 2D segmentation knowledge to 3D (Gaussians) and video for promptable segmentation of arbitrary objects.
Where is the object, and in what pose? — Pose Matching & Registration
Estimates the SE(3) transform $(R, t)$ between an observation and a known reference under a rigid-body assumption. Frame-to-frame pose tracking is a time-series state estimate that feeds manipulation (6) and world-model state initialization (7).
📦 Archived
🔭 Also notable: MegaPose · PVNet
How do we act on the world? — Action-Oriented Perception & Physics
Beyond seeing: infer the physical/functional properties needed for interaction, build the physics substrate world models run on, or output actions directly. Boundary with 7: learn a predictive model → 7; build or touch the world → 6 (boundary rule 3).
Note: the former sub-category 6-1 Dynamic 4D Reconstruction was dissolved — applying the placement question consistently, observed-interval dynamic reconstruction (4DGS, D-NeRF, UFO-4D) belongs to category 2 and future-dynamics prediction to category 7.
02_Physics-based/)Inverse-physics estimation of latent parameters (mass, friction, elasticity, articulation) and generation of simulation-ready assets.
Also notable: PAC-NeRF · Diff-Physics · PhyGround (physics-fidelity benchmark)
Maps functional possibilities — where and how an object can be manipulated — onto 3D space. Also notable: Contact-GraspNet · Affordance Diffusion · Where2Act
04_PolicyLearning/)Visuomotor policies and action representations: papers whose objective is the policy itself, without learning a world model.
Also notable: Diffusion Policy · ACT · OpenVLA · π0
How do we predict the world's next state? — Future-State Prediction & Action-Conditioned Rollout
Papers whose primary objective is learning the transition function $p(s_{t+1} \mid s_t, a_t)$ — predicting states not yet observed, whatever space the state lives in. Sub-categories follow the one mutually exclusive axis the community actually divides along: the representation space of the rollout. Function (Renderer/Simulator/Planner), conditioning, domain, and physics grounding are multi-valued attributes handled as tags, not directories.
01_LatentPrediction/)Future rollouts happen in latent space — no pixels are generated during planning or imagination, which is why latent planners are fast (V-JEPA 2 plans ~15× faster than pixel-generative baselines). Includes both reconstruction-free JEPA models and RSSM/Dreamer models with auxiliary decoders: the criterion is where the rollout lives, not whether a reconstruction loss exists.
Also notable: DINO-world · Dreamer 4
02_GenerativeVideo/)Future frames are generated directly by diffusion/autoregressive transformers. Visual fidelity is the strength; action conditioning is the practical line between a video generator and a world model.
Also notable: Sora 2 · Genie 3 · NVIDIA Cosmos · GAIA-2/GAIA-3 · Vista · PAN
Future/unobserved states output as explicit 3D structure (Gaussians, meshes) maintaining a persistent, physically explorable world state. Also notable: Marble (World Labs)
04_MultimodalReasoning/)World state modeled in interleaved verbal + visual representations: the world model lives inside the chain-of-thought of an LLM/UMM, with visual generation serving as world simulation for reasoning.
Also notable: PAN · Cosmos 3 (Reason) · ThinkMorph
Placement case law — every ruling applies the single question "what is the PRIMARY optimization objective?".
| Case | Ruling | Rationale |
|---|---|---|
| UFO-4D is 4D — why not 7? | 2 | Reconstructs + interpolates observed frames; no future rollout (rule 1) |
| GaussianGPT is autoregressive — why not 7? | 3 | Autoregressive rollout but static scene generation, no time dynamics or actions (rule 2); promotion candidate if actions are added |
| PhysForge — why not 7? | 6-2 | Generates physics-attached sim-ready assets; does not predict futures (rule 3) |
| Physical Representation Learning — why not 6-2? | 7-1 | Latent-space future prediction (JEPA) is the training objective |
| PhyWorld-style physics-aligned video generation? | 7-2 + physics tag | Objective is physics-aligned future video generation; pure fidelity benchmarks/evaluation go to 6-2 |
| AdaJEPA-style TTT of world models? | 7-1 | The object being adapted is the latent world model itself; the TTT mechanism cross-references Test3R/TTT3R (category 2) |
| Reasoning Visual World — why not 7-2? | 7-4 | Not video rollout: world modeling inside interleaved visual-verbal CoT — a multimodal representation space |
| Joint policy + world-model training (UWM-style)? | 7-2 + Planner tag | The joint loss weights future-observation prediction equally — learning, not consuming (rule 3); a policy paper consuming a frozen world model goes to 6 |
| DreamerV3 has a reconstruction decoder — why 7-1? | 7-1 | The 7-1 criterion is the rollout space, not the presence of a reconstruction loss: RSSM imagination is fully latent; the decoder is an auxiliary representation signal |
| I-JEPA is "JEPA" — why not 7-1? | 4-0 | JEPA is an architecture (embedding-space prediction), not a world model per se. Spatial masks of a static image → representation learning (4-0); temporal future states → world model (7-1) |
Category-7 papers carry these tags in their project README / study note (multi-valued attributes → tags, not directories):
| Tag axis | Values |
|---|---|
| Function (Fei-Fei Li taxonomy) | Renderer / Simulator / Planner |
| Conditioning | action / text / multimodal |
| Domain | driving / robotics / game / general |
| Physics grounding | implicit (data statistics) / explicit (physics alignment, simulator coupling) |
Category 7's sub-structure aligns with the 2025–2026 community-standard frameworks (kept as references, not directories):
<Category>/<NN_SubCategory>/<YYYY_PaperName>/
├── YYYY_PaperName.pdf # the paper itself
├── README.md # summary, links, BibTeX, placement notes
├── study_note.md # standardized concept mind-map (via /paper-to-note)
└── <implementation>/ # official or reference code, self-contained env
YYYY_PaperName/ by publication year. Planned sub-directories are created only when their first paper arrives — no empty scaffolding.Perception/point-cloud-analysis/ (historical, no numeric prefix) and Perception/00_UniversalEncoders/2026_PerceptionEncoder/ (published 2025; rename pending).YYYY_PaperName/ under the correct (sub-)category directory.README.md with summary, links, and BibTeX; category-7 papers also record their tags.study_note.md (concept mind-map format).CLAUDE.md in the same commit.33 commits
Jupyter Notebook
70.2%
Python
24.8%
C++
1.9%
TypeScript
1.3%
Cuda
1.2%