BlockGen-3D Dataset

Overview

BlockGen-3D is a large-scale dataset of voxelized 3D models with accompanying text descriptions, specifically designed for text-to-3D generation tasks. By processing and voxelizing models from the Objaverse dataset, we have created a standardized representation that is particularly suitable for training 3D diffusion models.

Our dataset provides two types of representations: shape-only models represented as binary occupancy grids, and colored models with full RGBA information. Each model is represented in a 32×32×32 voxel grid. The dataset contains 542,292 total samples, with:

• 515,177 training samples
• 27,115 test samples

Data Format and Structure

Every sample in our dataset consists of a voxel grid with accompanying metadata. The voxel grid uses a consistent 32³ resolution, with values structured as follows:

For shape-only data:

• voxels_occupancy: A binary grid of shape [1, 32, 32, 32] where each voxel is either empty (0) or occupied (1)

For colored data:

• voxels_colors: RGB color information with shape [3, 32, 32, 32], normalized to [0, 1]
• voxels_occupancy: The occupancy mask as described above

Each sample also includes rich metadata:

• Text descriptions derived from the original Objaverse dataset
• Categorization and tagging information
• Augmentation status and original file information
• Number of occupied voxels for quick filtering or analysis

Using the Dataset

Basic Loading and Inspection

from datasets import load_dataset

# Load the dataset
dataset = load_dataset("PeterAM4/blockgen-3d")

# Access splits
train_dataset = dataset["train"]
test_dataset = dataset["test"]

# Examine a sample
sample = train_dataset[0]
print(f"Sample description: {sample['name']}")
print(f"Number of occupied voxels: {sample['metadata']['num_occupied']}")

Working with Voxel Data

When working with the voxel data, you'll often want to handle both shape-only and colored samples uniformly. Here's a utility function that helps standardize the processing:

import torch

def process_voxel_data(sample, default_color=[0.5, 0.5, 0.5]):
    """Process voxel data with default colors for shape-only data.
    
    Args:
        sample: Dataset sample
        default_color: Default RGB values for shape-only models (default: gray)
    
    Returns:
        torch.Tensor: RGBA data with shape [4, 32, 32, 32]
    """
    occupancy = torch.from_numpy(sample['voxels_occupancy'])
    
    if sample['voxels_colors'] is not None:
        # Use provided colors for RGBA samples
        colors = torch.from_numpy(sample['voxels_colors'])
    else:
        # Apply default color to shape-only samples
        default_color = torch.tensor(default_color)[:, None, None, None]
        colors = default_color.repeat(1, 32, 32, 32) * occupancy
    
    # Combine into RGBA format
    rgba = torch.cat([colors, occupancy], dim=0)
    return rgba

Batch Processing with DataLoader

For training deep learning models, you'll likely want to use PyTorch's DataLoader. Here's how to set it up with a simple prompt strategy:

For basic text-to-3D generation, you can use the model names as prompts:

def collate_fn(batch):
    """Simple collate function using basic prompts."""
    return {
        'voxels': torch.stack([process_voxel_data(x) for x in batch]),
        'prompt': [x['name'] for x in batch]  # Using name field as prompt, could also use more complex prompts from categories and tags dict keys
    }

# Create DataLoader
dataloader = DataLoader(
    train_dataset,
    batch_size=32,
    shuffle=True,
    collate_fn=collate_fn
)

Visualization Examples

Dataset Usage Example - Showing voxelization process

Dataset Creation Process

Our dataset was created through the following steps:

1. Starting with the Objaverse dataset
2. Voxelizing 3D models at 32³ resolution
3. Preserving color information where available
4. Generating data augmentations through rotations
5. Creating train/test splits (95%/5% split ratio)

Training tips

• For shape-only models, use only the occupancy channel

• For colored models:

  • Apply colors only to occupied voxels
  • Use default colors for shape-only samples

Citation

If you use this dataset in your research, please cite:

@misc{blockgen2024,
  title={BlockGen-3D: A Large-Scale Dataset for Text-to-3D Voxel Generation},
  author={Peter A. Massih},
  year={2024},
  publisher={Hugging Face}
  url={https://huggingface.co./datasets/PeterAM4/blockgen-3d}
}

Limitations

• Fixed 32³ resolution limits fine detail representation
• Not all models have color information
• Augmentations are limited to rotations
• Voxelization may lose some geometric details