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Polish dataset card with detailed, paper-grounded documentation

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- Replace placeholder data schema with accurate modalities, per-step
state, and on-disk episode format
- Add simulation scenarios, contact-splat encoding, and data-generation
(Project Chrono + Ornstein-Uhlenbeck) details
- Document repository layout, data splits, selective downloading,
intended uses, and limitations
- Summarize the associated ChronoDreamer model and VLM-AUC protocol
- Keep citation as a neutral placeholder (paper pending)

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  1. README.md +158 -129
README.md CHANGED
@@ -18,96 +18,74 @@ tags:
18
  - simulator
19
  - friction
20
  - contact-dynamics
 
21
  - physics-simulation
22
  - dynamics-prediction
 
 
 
23
  pretty_name: DreamerBench
24
  size_categories:
25
  - n<1K
26
  ---
27
 
28
- # Dataset Card for DreamerBench
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
29
 
30
  ## Table of Contents
 
 
 
 
31
  - [Dataset Description](#dataset-description)
32
- - [Dataset Summary](#dataset-summary)
33
- - [Supported Tasks and Leaderboards](#supported-tasks-and-leaderboards)
34
- - [Languages](#languages)
 
35
  - [Dataset Structure](#dataset-structure)
36
- - [Data Instances](#data-instances)
37
- - [Data Fields](#data-fields)
 
38
  - [Data Splits](#data-splits)
39
  - [Loading the Data](#loading-the-data)
40
- - [Dataset Creation](#dataset-creation)
41
- - [Curation Rationale](#curation-rationale)
42
- - [Source Data](#source-data)
43
- - [Personal and Sensitive Information](#personal-and-sensitive-information)
44
- - [Considerations for Using the Data](#considerations-for-using-the-data)
45
- - [Social Impact of Dataset](#social-impact-of-dataset)
46
- - [Discussion of Biases](#discussion-of-biases)
47
- - [Other Known Limitations](#other-known-limitations)
48
  - [Additional Information](#additional-information)
49
- - [Dataset Curators](#dataset-curators)
50
- - [Licensing Information](#licensing-information)
51
- - [Citation Information](#citation-information)
52
-
53
- ## Dataset Description
54
-
55
- - **Homepage:** https://huggingface.co/datasets/zzhou292/DreamerBench
56
- - **Repository:** https://github.com/uwsbel/ChronoDreamer
57
- - **Paper:** [TODO: Link to arXiv paper if available]
58
- - **Point of Contact:** Json Zhou, zzhou292@wisc.edu
59
-
60
- ### Dataset Summary
61
 
62
- **DreamerBench** is a large-scale dataset designed for training and evaluating **World Models** in robotics applications. Unlike standard visual-only datasets, DreamerBench explicitly focuses on physical interaction dynamics, specifically **friction** and **contact data**.
63
 
64
- The dataset is generated using Project Chrono (https://projectchrono.org/), simulating diverse robotic interaction scenarios where precise modeling of physical forces is critical. It includes pre-computed **encodings** to facilitate efficient training of latent dynamics models.
65
 
66
- Key features:
67
- * **Physical Fidelity:** detailed ground-truth annotations for coefficient of friction, contact forces, and slip.
68
- * **Multi-Modal:** Contains visual observations (RGB/Depth), proprioceptive states, and explicit physics parameters.
69
- * **World Model Ready:** Structured to support next-step prediction and imaginary rollout training (Dreamer-style architectures).
70
 
71
- ### Supported Tasks and Leaderboards
72
 
73
- * **World Modeling / Dynamics Learning:** Training models to predict future states ($s_{t+1}$) given current state ($s_t$) and action ($a_t$).
74
- * **Offline Reinforcement Learning:** Learning policies from the provided simulator trajectories without active environmental interaction.
75
- * **Sim-to-Real Adaptation:** Using the varied friction/contact parameters to train robust policies that generalize to real-world physics.
76
 
77
- ### Languages
78
-
79
- The dataset is **non-linguistic**: it consists of physics-based simulation rollouts (visual, proprioceptive, and contact/friction signals). The only natural-language content is English-language metadata, field names, and documentation (BCP-47 code: `en`).
80
-
81
- ## Dataset Structure
82
 
83
- ### Data Instances
84
-
85
- Each instance in the dataset represents a **trajectory** or **episode** of a robot interacting with the environment.
86
-
87
- **Example structure (JSON/Parquet format):**
88
-
89
- ```json
90
- {
91
- "episode_id": "traj_001",
92
- "steps": 1000,
93
- "observations": {
94
- "rgb": [Array of (1000, 64, 64, 3) images],
95
- "depth": [Array of (1000, 64, 64, 1) images],
96
- "proprioception": [Array of joint angles/velocities]
97
- },
98
- "actions": [Array of control inputs],
99
- "rewards": [Array of float scalars],
100
- "physics_data": {
101
- "contact_forces": [Array of 3D force vectors],
102
- "friction_coefficient": 0.8,
103
- "contact_detected": [Binary array]
104
- },
105
- "encoding": [Pre-computed latent vectors, e.g., VAE or RSSM states]
106
- }
107
- ```
108
-
109
- **Example scenarios:**
110
- <h3>Visual Data Samples</h3>
111
  <p>
112
  The clips below are <strong>representative, time-synchronized visualizations</strong> of four
113
  example scenarios. Each scenario is shown from three synchronized camera views
@@ -189,29 +167,97 @@ Each instance in the dataset represents a **trajectory** or **episode** of a rob
189
  </tbody>
190
  </table>
191
 
192
- ### Data Fields
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
193
 
194
- Each episode/trajectory exposes the following fields (mirroring the schema shown above):
195
 
196
- | Field | Type | Description |
197
- |-------|------|-------------|
198
- | `episode_id` | string | Unique trajectory identifier (e.g., `traj_001`). |
199
- | `steps` | int | Number of timesteps in the episode. |
200
- | `observations.rgb` | array | RGB frames, shape `(steps, 64, 64, 3)`. |
201
- | `observations.depth` | array | Depth frames, shape `(steps, 64, 64, 1)`. |
202
- | `observations.proprioception` | array | Robot joint angles / velocities per step. |
203
- | `actions` | array | Control inputs applied at each step. |
204
- | `rewards` | array | Per-step scalar rewards. |
205
- | `physics_data.contact_forces` | array | 3D contact-force vectors per step. |
206
- | `physics_data.friction_coefficient` | float | Coefficient of friction for the interaction. |
207
- | `physics_data.contact_detected` | array | Binary contact indicator per step. |
208
- | `encoding` | array | Pre-computed latent states (e.g., VAE/RSSM); see `cosmos_tokenized/` for Cosmos Tokenizer DI 8×8 latents. |
209
 
210
- > The inline previews above are rendered at 256×256 for display, while the stored RGB/Depth observation tensors are 64×64 as listed in the schema.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
211
 
212
  ### Data Splits
213
 
214
- The dataset is organized by **interaction scenario**, each provided as sharded ZIP archives plus a held-out evaluation split:
215
 
216
  | Scenario | Training shards | Eval split |
217
  |----------|-----------------|------------|
@@ -220,16 +266,11 @@ The dataset is organized by **interaction scenario**, each provided as sharded Z
220
  | `waterbottle_coca` | `waterbottle_coca_00.zip`, `_01`, `_02` | `waterbottle_coca_eval.zip` |
221
  | `fea_flashlight` | `fea_flashlight_00.zip`, `_01`, `_02` | `fea_flashlight_eval.zip` |
222
 
223
- **Additional artifacts:**
224
-
225
- - **`cosmos_tokenized/`** — latent encodings produced with the **Cosmos Tokenizer DI 8×8** autoencoder. Provided per scenario (`*_60`, `*_120`, `*_180`, `*_eval`) and as combined aggregates (`combined_240`, `combined_480`, `combined_720`, `combined_eval`).
226
- - **`pretrained_ckpt/`** — pretrained World-Model checkpoints for use with the ChronoDreamer pipeline: `mode_0/` and `mode_1/` (`epoch_0`–`epoch_9`), plus an `fea_flashlight/` ablation (`epoch_4`–`epoch_7`).
227
- - **`inference_results.zip`** — sample rollout/inference outputs.
228
- - **`assets/previews/`** — short MP4 preview clips used in the table above.
229
 
230
  ### Loading the Data
231
 
232
- This is a large, Git-LFS–backed dataset — **avoid cloning or downloading everything**. Fetch only the specific archives you need with `huggingface_hub`:
233
 
234
  ```python
235
  from huggingface_hub import hf_hub_download
@@ -259,58 +300,46 @@ files = HfApi().list_repo_files("zzhou292/DreamerBench", repo_type="dataset")
259
  print("\n".join(files))
260
  ```
261
 
262
- ## Dataset Creation
263
-
264
- ### Curation Rationale
265
 
266
- DreamerBench was created to provide **physics-grounded** training data for world models. Most video and interaction datasets capture appearance but omit the underlying contact and friction dynamics that govern manipulation. By generating trajectories in a high-fidelity physics simulator, DreamerBench pairs visual observations with ground-truth contact forces, friction coefficients, and slip — enabling models to learn dynamics rather than only visual correlations.
267
 
268
- ### Source Data
269
 
270
- All data is **synthetically generated** using [Project Chrono](https://projectchrono.org/), an open-source multi-physics simulation engine. Scenarios are named after the interacting objects (`flashlight_box`, `flashlight_coca`, `waterbottle_coca`, and `fea_flashlight` — a flashlight variant used for the ablation study documented in `pretrained_ckpt/fea_flashlight/`). Each episode is rendered from multiple synchronized viewpoints (Ego, Side 1, Side 2) together with a contact-splat visualization, and latent encodings are produced with the Cosmos Tokenizer DI 8×8 autoencoder. No human-subject, web-scraped, or otherwise externally sourced data is involved.
271
 
272
- ### Personal and Sensitive Information
273
 
274
- The dataset contains **no personal, private, or sensitive information**. All content is procedurally generated in simulation and does not depict real people, locations, or identifiable entities.
275
 
276
- ## Considerations for Using the Data
277
 
278
- ### Social Impact of Dataset
279
 
280
- DreamerBench is intended to advance research in physically grounded world models, model-based reinforcement learning, and robotic manipulation. Because it is fully synthetic, it carries low direct social risk and can reduce the cost and safety concerns associated with large-scale real-robot data collection.
281
 
282
- ### Discussion of Biases
 
 
 
283
 
284
- The data reflects the modeling assumptions of the simulator (material properties, contact models, friction parameters, camera placement, and the specific object set). Models trained solely on this data may inherit those assumptions and may not generalize to dynamics or objects outside the simulated distribution.
285
 
286
- ### Other Known Limitations
287
-
288
- - **Sim-to-real gap:** simulated contact/friction dynamics are approximations of real-world physics.
289
- - **Limited diversity:** a small set of curated interaction scenarios and objects.
290
- - **Low observation resolution:** stored observations are 64×64 (previews are rendered at 256×256).
291
- - **Storage/bandwidth:** files are distributed as Git-LFS ZIP archives; download selectively (see [Loading the Data](#loading-the-data)).
292
 
293
  ## Additional Information
294
 
295
- ### Dataset Curators
296
-
297
- DreamerBench is developed as part of the **ChronoDreamer** project (https://github.com/uwsbel/ChronoDreamer). Point of contact: **Json Zhou** (`zzhou292@wisc.edu`).
298
-
299
- ### Licensing Information
300
 
301
  Released under the **MIT License**.
302
 
303
- ### Citation Information
304
 
305
- If you use DreamerBench, please cite the project. A formal paper is forthcoming; until then, the placeholder below may be used (update the title, authors, and year once published):
306
 
307
- ```bibtex
308
- @misc{dreamerbench2025,
309
- title = {DreamerBench: A Physics-Grounded Dataset for World Models},
310
- author = {Zhou, Json},
311
- howpublished = {Hugging Face Datasets},
312
- year = {2025},
313
- url = {https://huggingface.co/datasets/zzhou292/DreamerBench},
314
- note = {Project: https://github.com/uwsbel/ChronoDreamer}
315
- }
316
- ```
 
18
  - simulator
19
  - friction
20
  - contact-dynamics
21
+ - contact-mechanics
22
  - physics-simulation
23
  - dynamics-prediction
24
+ - robotic-manipulation
25
+ - gaussian-splat
26
+ - project-chrono
27
  pretty_name: DreamerBench
28
  size_categories:
29
  - n<1K
30
  ---
31
 
32
+ # DreamerBench
33
+
34
+ **A simulator-generated, multimodal benchmark for world models in contact-rich, frictional robotic manipulation.**
35
+
36
+ DreamerBench provides time-synchronized RGB observations, camera-aligned **contact-splat** visualizations, proprioception, low-level control actions, and dense physics annotations (contact forces, friction coefficients, and contact-mode flags), together with **precomputed discrete visual latents** for token-based world models. It is the dataset used to train and evaluate **ChronoDreamer**, an action-conditioned world model for contact-rich manipulation.
37
+
38
+ | | |
39
+ |---|---|
40
+ | **Code** | <https://github.com/uwsbel/ChronoDreamer> |
41
+ | **Dataset** | <https://huggingface.co/datasets/zzhou292/DreamerBench> |
42
+ | **Generator** | [Project Chrono](https://projectchrono.org/) multi-physics engine |
43
+ | **License** | MIT |
44
+ | **Point of contact** | Json Zhou (`zzhou292@wisc.edu`) |
45
+
46
+ > [!NOTE]
47
+ > DreamerBench is a *focused* benchmark (~12 hours of interaction data), deliberately narrowed to contact-rich tabletop dynamics rather than a broad, web-scale corpus. Its value is the explicit contact/friction supervision that general video datasets omit.
48
 
49
  ## Table of Contents
50
+
51
+ - [Overview](#overview)
52
+ - [Highlights](#highlights)
53
+ - [Visual Data Samples](#visual-data-samples)
54
  - [Dataset Description](#dataset-description)
55
+ - [Simulation Scenarios](#simulation-scenarios)
56
+ - [Data Modalities and Per-Step State](#data-modalities-and-per-step-state)
57
+ - [Contact Encoding via Depth-Weighted Gaussian Splats](#contact-encoding-via-depth-weighted-gaussian-splats)
58
+ - [Data Generation](#data-generation)
59
  - [Dataset Structure](#dataset-structure)
60
+ - [Repository Layout](#repository-layout)
61
+ - [On-Disk Episode Format](#on-disk-episode-format)
62
+ - [Precomputed Latents (Cosmos DI8x8)](#precomputed-latents-cosmos-di8x8)
63
  - [Data Splits](#data-splits)
64
  - [Loading the Data](#loading-the-data)
65
+ - [Associated Model and Benchmark](#associated-model-and-benchmark)
66
+ - [ChronoDreamer World Model](#chronodreamer-world-model)
67
+ - [VLM-AUC Evaluation](#vlm-auc-evaluation)
68
+ - [Intended Uses and Tasks](#intended-uses-and-tasks)
69
+ - [Limitations](#limitations)
 
 
 
70
  - [Additional Information](#additional-information)
71
+ - [Licensing](#licensing)
72
+ - [Citation](#citation)
73
+ - [Acknowledgments](#acknowledgments)
 
 
 
 
 
 
 
 
 
74
 
75
+ ## Overview
76
 
77
+ World models predict how a scene evolves under an agent's actions, enabling planning by imagination. Most video-prediction datasets, however, optimize for visual plausibility and treat **contact** as an implicit, unlabeled phenomenon: friction coefficients are fixed or weakly randomized, contact forces are rarely logged, and evaluation measures task reward or perceptual quality rather than contact-mechanics accuracy. This is precisely the regime that determines whether a manipulation trajectory succeeds.
78
 
79
+ DreamerBench targets this gap. It models **non-smooth hybrid dynamics** with intermittent contact, Coulomb friction, and stick–slip transitions, and exposes the underlying physical quantities as first-class, supervised signals alongside the rendered video.
 
 
 
80
 
81
+ ### Highlights
82
 
83
+ - **Contact-centric supervision.** Contact modes (no-contact / sticking / sliding / separating), normal and tangential forces, and friction parameters are logged with every frame and projected into camera-aligned **contact-splat** images suitable as a supervised output channel.
84
+ - **Multimodal but tractable.** Synchronized RGB, contact splats, and proprioception are provided alongside **precomputed Cosmos DI8×8 FSQ tokens**, so models can train in pixel space or in a discrete latent space without re-running encoders.
85
+ - **Controlled physical variation.** Friction coefficients, object inertial parameters, initial conditions, and control signals are varied across seeds within a small family of scenarios, supporting the study of generalization under physical-parameter shift.
86
 
87
+ ### Visual Data Samples
 
 
 
 
88
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
89
  <p>
90
  The clips below are <strong>representative, time-synchronized visualizations</strong> of four
91
  example scenarios. Each scenario is shown from three synchronized camera views
 
167
  </tbody>
168
  </table>
169
 
170
+ In the contact-splat column, **red** encodes contact-force magnitude and **green–blue** encodes the projected force direction in the image plane (see [Contact Encoding](#contact-encoding-via-depth-weighted-gaussian-splats)).
171
+
172
+ ## Dataset Description
173
+
174
+ ### Simulation Scenarios
175
+
176
+ DreamerBench currently covers four tabletop interaction motifs involving a hand-held tool and one or more objects. Each scenario provides synchronized ego/side RGB views, contact-splat images, proprioception, low-level actions, and physics annotations, with discrete FSQ tokens precomputed via the Cosmos DI8×8 tokenizer.
177
+
178
+ | Scenario | Objects and interaction | Dominant contact behavior |
179
+ |----------|-------------------------|---------------------------|
180
+ | `flashlight_box` | Hand-held tool and a box on a planar surface | Sliding and pushing |
181
+ | `flashlight_coca` | Tool and a tall cylindrical container | Sliding and rolling contact |
182
+ | `waterbottle_coca` | Bottle interacting with a cylinder | Combined sliding and rolling along the table |
183
+ | `fea_flashlight` | Four tetrahedron-meshed **finite-element (FEA)** deformable beams and two standing flashlights (rigid bodies) | Deformable contact and beam bending |
184
+
185
+ For each scenario, multiple random seeds perturb surface friction coefficients, initial object poses and velocities, and the control trajectory, producing families of related but distinct contact sequences.
186
+
187
+ ### Data Modalities and Per-Step State
188
+
189
+ At each simulation step `t`, DreamerBench logs a state tuple `s_t = (o_rgb, o_contact, q, q̇, f_contact, μ, c)`, together with a low-level action `a_t` and, optionally, a task reward `r_t`. An episode is the sequence `τ = (s_0, a_0, r_0, s_1, …, s_T)`. Episodes last **300–600 steps**, chosen so that objects undergo multiple contact-mode transitions (impact, stick–slip, rolling, settling).
190
+
191
+ | Signal | Symbol | Description |
192
+ |--------|:------:|-------------|
193
+ | RGB views | `o_rgb` | Egocentric and side-camera RGB frames, rendered at **256×256**. |
194
+ | Contact splat | `o_contact` | 256×256 camera-aligned image encoding contact-force magnitude (red) and projected direction (green/blue). |
195
+ | Proprioception | `q`, `q̇` | Robot joint positions and velocities (`N_j = 4` joint channels). |
196
+ | Action | `a` | 3-D end-effector velocity command `(x, y, z)`, generated by an Ornstein–Uhlenbeck process. |
197
+ | Contact forces | `f_contact` | Per-contact 3-D normal and tangential forces (impulses discretized over Δt). |
198
+ | Friction | `μ` | Coulomb friction coefficients (e.g., static/kinetic `(μ_s, μ_k)`), varied across seeds. |
199
+ | Contact mode | `c` | Discrete flag: no-contact / sticking / sliding / separating. |
200
+ | Reward *(optional)* | `r` | Scalar task reward, when a task is defined. |
201
+ | Precomputed tokens | `z` | Cosmos DI8×8 FSQ discrete tokens (32×32 grid, vocabulary `V = 64,000`) for the RGB and contact streams. |
202
 
203
+ ### Contact Encoding via Depth-Weighted Gaussian Splats
204
 
205
+ Rather than storing contact as a sparse list of points, DreamerBench renders, at every step, a **contact-splat image** that aggregates all active contacts into a single RGB frame aligned with a reference camera — a format that vision backbones and video tokenizers can consume directly.
 
 
 
 
 
 
 
 
 
 
 
 
206
 
207
+ For each contact `i` with 3-D position `p_i` and force `f_i`:
208
+
209
+ 1. The point is transformed into the camera frame and projected to a pixel via a pinhole model; a second point displaced along `f_i` is projected to recover the **in-plane force direction**.
210
+ 2. The **red** channel stores the clipped, normalized force magnitude; the **green/blue** channels store the normalized 2-D direction.
211
+ 3. Each contact is splatted as an isotropic Gaussian whose radius grows with force magnitude, multiplied by a **depth weight** `exp(-X_i / τ_depth)` so that nearer contacts dominate.
212
+ 4. Contributions are accumulated and per-pixel normalized, yielding a soft z-buffer over Gaussian "surfels" that compactly encodes spatial footprint, approximate pressure, and projected force direction.
213
+
214
+ ### Data Generation
215
+
216
+ Trajectories are produced with **Project Chrono**, configured as a multi-physics engine with rigid and (optionally) flexible bodies, Coulomb friction, and penalty- or constraint-based contact handling. The continuous-time dynamics form a non-smooth hybrid ODE/DAE system; DreamerBench records a discretized version suited to sequence modeling.
217
+
218
+ To excite rich, repeatable contact behavior without high-frequency jitter, the joystick command channel is driven by a three-dimensional **Ornstein–Uhlenbeck (OU)** process — temporally correlated colored noise — post-processed through a minimum-norm constraint, a deadzone, and a clipped kinematic integrator before being passed to an inverse-kinematics solver. This consistently drives sliding, rolling, and intermittent sticking while avoiding degenerate near-static trajectories, and it admits straightforward ablations (e.g., varying the correlation time or substituting i.i.d. Gaussian noise).
219
+
220
+ ## Dataset Structure
221
+
222
+ ### Repository Layout
223
+
224
+ ```text
225
+ DreamerBench/
226
+ ├── flashlight_box_{00,01,02,eval}.zip # raw episodes: RGB, contact splat, proprio, actions, physics
227
+ ├── flashlight_coca_{00,01,02,eval}.zip
228
+ ├── waterbottle_coca_{00,01,02,eval}.zip
229
+ ├── fea_flashlight_{00,01,02,eval}.zip
230
+ ├── cosmos_tokenized/ # precomputed Cosmos DI8x8 FSQ latents
231
+ │ ├── <scenario>_{60,120,180,eval}_tokenized.zip
232
+ │ └── combined_{240,480,720,eval}_tokenized.zip
233
+ ├── pretrained_ckpt/ # ChronoDreamer world-model checkpoints
234
+ │ ├── mode_0/epoch_{0..9}.zip # training configuration 0
235
+ │ ├── mode_1/epoch_{0..9}.zip # training configuration 1
236
+ │ └── fea_flashlight/epoch_{4..7}.zip # FEA-only ablation study
237
+ ├── inference_results.zip # rollouts + VLM-AUC evaluation artifacts
238
+ ├── assets/previews/ # short MP4 preview clips (shown above)
239
+ └── README.md
240
+ ```
241
+
242
+ All archives are tracked with **Git LFS**.
243
+
244
+ ### On-Disk Episode Format
245
+
246
+ Each scenario archive (e.g., `flashlight_box_00.zip`) contains multiple episodes and auxiliary files:
247
+
248
+ - arrays for RGB and contact-splat images, proprioception, actions, and physics annotations;
249
+ - precomputed discrete visual tokens for the RGB and contact streams (e.g., `video.bin`, `contact_splat.bin`), obtained from the Cosmos DI8×8 tokenizer via finite-scalar quantization;
250
+ - JSON metadata describing the token grid size `S`, vocabulary size `V`, frame count, frame rate, and segmentation into episodes (segment IDs).
251
+
252
+ This layout streams naturally in common training stacks (PyTorch, JAX), either as variable-length episodes or as a single concatenated sequence with associated segment IDs.
253
+
254
+ ### Precomputed Latents (Cosmos DI8x8)
255
+
256
+ RGB and contact-splat frames are tokenized with the **NVIDIA Cosmos-0.1-Tokenizer-DI8×8**, which maps a 256×256 image to a **32×32** grid of discrete tokens (8× spatial compression per axis) via **Finite-Scalar Quantization (FSQ)**. Six latent channels are quantized with per-channel levels `(8, 8, 8, 5, 5, 5)`, giving a vocabulary of `V = 64,000` with no learnable codebook. The `cosmos_tokenized/` archives ship these latents per scenario and as combined aggregates so that token-based world models avoid repeated encoding.
257
 
258
  ### Data Splits
259
 
260
+ The dataset is organized by **interaction scenario**, each provided as sharded training archives plus a held-out evaluation split:
261
 
262
  | Scenario | Training shards | Eval split |
263
  |----------|-----------------|------------|
 
266
  | `waterbottle_coca` | `waterbottle_coca_00.zip`, `_01`, `_02` | `waterbottle_coca_eval.zip` |
267
  | `fea_flashlight` | `fea_flashlight_00.zip`, `_01`, `_02` | `fea_flashlight_eval.zip` |
268
 
269
+ For the VLM-AUC evaluation, each scenario additionally contributes **72 human-labeled samples** (binary collision / no-collision); the positive/negative ratio reflects the natural contact frequency and is not balanced.
 
 
 
 
 
270
 
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  ### Loading the Data
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+ This dataset is large and Git-LFS–backed — **avoid cloning or downloading everything**. Fetch only the specific archives you need with `huggingface_hub`:
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  ```python
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  from huggingface_hub import hf_hub_download
 
300
  print("\n".join(files))
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  ```
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+ ## Associated Model and Benchmark
 
 
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+ ### ChronoDreamer World Model
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+ DreamerBench is the training and evaluation substrate for **ChronoDreamer**, an action-conditioned world model. Given a history of egocentric RGB frames, actions, and joint states, ChronoDreamer jointly predicts **future video tokens, contact-splat tokens, and joint angles**. It operates on the precomputed Cosmos DI8×8 tokens with a **spatial-temporal transformer** (24 layers, hidden size 256, 8 heads; factorized spatial and causal-temporal attention) trained with a **MaskGIT-style** masked-prediction objective over a factorized token vocabulary. The model has roughly **30–50M parameters** and was trained for 10 epochs on four NVIDIA A100 GPUs (~10 days) over ~12 hours of interaction data.
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+ Pretrained checkpoints are provided under `pretrained_ckpt/` (`mode_0`, `mode_1`, and an `fea_flashlight` ablation).
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+ ### VLM-AUC Evaluation
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+ **VLM-AUC** is an offline protocol for measuring world-model quality without ground-truth forces at test time. A predicted rollout is scored for collision severity on a symmetric 1–5 scale by an **ensemble of five prompt variants** (baseline, evidence-first CoT, conservative gating, future-only temporal boundary, and counterfactual verification); the averaged ensemble score's **AUC** against human binary collision labels is computed via the **Wilcoxon–Mann–Whitney** statistic, making it robust to class imbalance.
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+ Three open-weight judges are evaluated — **Llama 3.2 90B**, **Gemma 3 27B**, and **Qwen3.5 122B** — across three conditions: ground truth (GT), epoch-10 predictions, and epoch-1 predictions. The protocol expects the ordering `AUC(GT) ≥ AUC(Ep.10) ≥ AUC(Ep.1)`. At the aggregate level this ordering holds for the larger judges, while the smallest judge inverts the epoch sub-ordering, consistent with reduced calibration at smaller scale. Complete evaluation artifacts — inference logs, reasoning traces, raw outputs, and parsed scores — are archived in `inference_results.zip`.
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+ ## Intended Uses and Tasks
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+ DreamerBench supports world models that must account for both visual appearance and low-level contact physics:
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+ - **One-step and multi-step prediction** in pixel or latent space (image reconstruction error, proprioception error, contact-mode cross-entropy; rollout-degradation metrics such as SSIM and force-sequence deviation).
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+ - **Contact- and friction-specific evaluation**: contact-onset and mode prediction (precision/recall/F1 on `c`), normal/tangential force regression, and robustness under friction-domain shift.
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+ - **Contact-implicit / contact-aware planning** and **model-based reinforcement learning** from offline trajectories.
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+ - **World-model assessment** via the VLM-AUC protocol.
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+ ## Limitations
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+ - **Simulation only.** All data is generated in Project Chrono and inherits its modeling assumptions; a sim-to-real gap remains.
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+ - **Modest volume and contact sparsity.** ~12 hours of data, and contact events are a small fraction of frames — likely contributing to post-contact blurring observed in trained models.
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+ - **Narrow coverage.** Four scenarios and a single robot morphology; far fewer than broad manipulation benchmarks, and generalization across embodiments is not probed.
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+ - **Evaluation breadth.** The released results focus on video cross-entropy, LPIPS, joint-angle MSE, and VLM-AUC; the full contact/friction metric suite and external world-model baselines (Dreamer, PlaNet, Genie-style) are left to future work.
 
 
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  ## Additional Information
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+ ### Licensing
 
 
 
 
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  Released under the **MIT License**.
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+ ### Citation
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+ A citation for DreamerBench will be provided here at a later date.
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+ ### Acknowledgments
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+
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+ Developed by the **Simulation-Based Engineering Laboratory (SBEL)** at the University of Wisconsin–Madison. This work was supported in part by the National Science Foundation under Award No. CMMI-2153855, and used the Euler cluster at UW–Madison and the [Project Chrono](https://projectchrono.org/) simulation infrastructure.