README.md

DONUT (Dataset Of MaNifold strUcTures)

This repository contains a dataset of 3D samples made of watertight meshes and corresponding point clouds. Each sample is composed of one or several watertight mesh components and one 8192-point cloud representation.

The dataset contains 29,517 samples in total.

Overview

The figure below shows a few samples from the dataset together with their labels.

Contents

The repository is organized as follows:

.
├── metadata.csv
├── obj/
│   ├── shard_0/
│   ├── shard_1/
│   └── shard_2/
└── pcd/
    ├── shard_0/
    ├── shard_1/
    └── shard_2/

• obj/ contains the mesh files as .npz archives.
• pcd/ contains the point clouds as .npy files.
• metadata.csv contains one row per sample with topological metadata.

There are 29,517 mesh files in obj/ and 29,517 point cloud files in pcd/.

File Format

Meshes

Each mesh sample is stored as an .npz file in obj/. The archive contains:

• vertices.npy
• faces.npy

A sample may contain one or several watertight connected mesh components.

Point Clouds

Each point cloud sample is stored as a .npy file in pcd/.

Each point cloud contains 8192 points and corresponds to the sample with the same id.

Sample Identification

Each sample is identified by a unique id string.

The same id is used in:

• the filename in obj/
• the filename in pcd/
• the id column in metadata.csv

For example, if a sample has id abc123, its files are:

• obj/.../abc123.npz
• pcd/.../abc123.npy

Metadata

metadata.csv contains the following columns:

• id: unique identifier of the sample
• genus: total number of holes across all mesh components in the sample
• components: total number of connected mesh components in the sample
• sample_code: array of 6 integers describing how many components of each genus are present

Meaning of sample_code

sample_code is an array of 6 integers:

[n0, n1, n2, n3, n4, n5]

Here, ni is the number of mesh components in the sample whose genus is i.

So:

• n0 is the number of genus-0 components
• n1 is the number of genus-1 components
• n2 is the number of genus-2 components
• n3 is the number of genus-3 components
• n4 is the number of genus-4 components
• n5 is the number of genus-5 components

From sample_code, the metadata values are computed as:

genus = sum(i * ni for i in [0, 1, 2, 3, 4, 5])
components = sum(ni for i in [0, 1, 2, 3, 4, 5])

In other words:

• genus is the total number of holes in the full sample
• components is the total number of connected components in the full sample

The distribution of labels in the dataset is shown below.

Examples

sample_code = [2, 1, 0, 0, 0, 0]

This means:

• 2 components of genus 0
• 1 component of genus 1
• total genus = 0 * 2 + 1 * 1 = 1
• total components = 2 + 1 = 3

Summary

DONUT is a dataset of 29,517 samples of manifold 3D structures.

Each sample provides:

• one mesh file in .npz format
• one 8192-point cloud in .npy format
• one metadata entry in metadata.csv

The metadata describes the global topology of each sample through its total genus, number of connected components, and component-wise genus distribution.