README.md

---
license: cc-by-4.0
pretty_name: MechAtlas
size_categories:
  - 10K<n<100K
tags:
  - benchmark
  - cad
  - 3d
  - mechanical-engineering
  - engineering-drawings
  - drawing-to-cad
extra_gated_heading: "Request access to MechAtlas"
extra_gated_description: "Please provide your affiliation and research purpose. Access requests are reviewed manually."
extra_gated_button_content: "Submit request"
extra_gated_fields:
  Affiliation: text
  Research purpose: text
---

# MechAtlas

## Dataset Summary

**MechAtlas** is a benchmark containing **49,687 paired samples** of
2D mechanical engineering drawings and corresponding 3D CAD models
from real-world industrial production.

Each sample consists of:

- A **PDF drawing** representing the 2D engineering documentation.
- A **STEP model** representing the corresponding 3D CAD geometry.

The dataset supports research on engineering drawing understanding,
drawing-to-CAD reconstruction, and correspondence between 2D drawings
and 3D geometry.

## Dataset Statistics

| Item | Count |
| --- | ---: |
| Paired samples | 49,687 |
| PDF drawings | 49,687 |
| STEP models | 49,687 |
| Total data files | 99,374 |

Each PDF–STEP pair counts as **one sample**. The total file count
excludes repository documentation and other administrative files.

## Data Source and Creation

The engineering drawings and CAD models were manually created by
professional engineers.

The original engineering drawings underwent rigorous technical review
and formal approval, including signatures and stamps, and were
ultimately used in real-world industrial production.

## Dataset Structure

### File Formats

| Component | Extension | Description |
| --- | --- | --- |
| Engineering drawing | `.pdf` | 2D mechanical engineering documentation |
| CAD model | `.step` | Corresponding 3D CAD geometry in STEP format |

### Directory Organization

The underlying data is organized into two top-level directories,
with numbered subdirectories grouping the files:

```text
MechAtlas/
├── PDF/
│   ├── 0000/
│   │   └── 00001495.pdf
│   ├── 0001/
│   ├── 0002/
│   ├── 0003/
│   └── 0004/
└── STEP/
    ├── 0000/
    │   └── 00001495.step
    ├── 0001/
    ├── 0002/
    ├── 0003/
    └── 0004/
```

The tree above illustrates the directory layout and one example pair.

### Sample Identification and Pairing

The filename without its extension serves as the sample identifier.
A PDF drawing and a STEP model with the same identifier form a pair.

For example:

| Sample ID | PDF drawing | STEP model |
| --- | --- | --- |
| `00001495` | `PDF/0000/00001495.pdf` | `STEP/0000/00001495.step` |

All **49,687 sample identifiers** have both a PDF drawing and a STEP
model in the prepared data package.

Treat sample identifiers as strings and preserve their leading zeros
when extracting, indexing, or processing the files.

## Access and Usage

### Requesting Access

MechAtlas is distributed as a gated dataset with manual approval.

To request access:

1. Sign in to your Hugging Face account.
2. Provide your affiliation and research purpose in the access request form.
3. Submit your request for review.
4. After approval, download the data from the **Files and versions** tab.

### Working with the Files

Open PDF drawings with a PDF viewer and import STEP models using
CAD software or a geometry-processing library that supports STEP.

When working with archive downloads, extract the files before use
and preserve the original sample identifiers.

Match each drawing to its corresponding CAD model using the
shared filename identifier.

## License

MechAtlas is distributed under the
[Creative Commons Attribution 4.0 International License
(CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/).

Use and redistribution must comply with the license terms.
The access request process governs downloads from this repository;
the license governs use and redistribution of the data.