pretty_name: LightGenBench
license: other
license_name: mixed-cc
viewer: false
tags:
- 3d
- pbr
- emission
- texture
- uv-atlas
- voxels
- multiview
size_categories:
- 10K<n<100K
LightGenBench: A Benchmark for 3D Emission Generation
LightGenBench is a dataset of emissive 3D objects for training and evaluating emission texture generation. Its key characteristics:
- Scale and source: 36,826 emissive shapes from TexVerse (Sketchfab models), each with albedo, metallic, roughness, opacity and an emission map. It is curated from the 859k TexVerse models.
- Three representations: every shape comes as a 512×512 UV atlas, 256³ sparse voxels and six orthographic 512×512 views, the inputs of UV-, voxel- and multiview-based texture generators.
- Splits: train 36,426, val 200, test 200 shapes; val and test are category-stratified.
Questions or problems: open a discussion on this repository.
Download
The repository holds about 117 GB:
README.md this card
splits.json the split of each shape: {"train": [uuid, ...], "val": [...], "test": [...]}
metadata.parquet one row per shape: uuid, split, shard, category, license, author, author_username, source_url
checksums.sha256 sha256 of every other file, to verify a download
assets/ the images this card shows
data/ <split>/<kind>/<kind>-<shard>.tar, kind: atlas, voxels, multiview, thumbnail
The shapes are sorted based on uuids and cut into shards of 1,000 shapes: train has 37 shards (the last holds 426), val and test have one for each (200 per shard), 39 shards in all. A shard is stored as four tars: the three representations (UV atlas, O-Voxels, multiview images) and the Sketchfab thumbnail; the four tars of a shard hold the files of the same uuids. For example:
data/train/atlas/atlas-00007.tar <uuid>/atlas.npz
data/train/voxels/voxels-00007.tar <uuid>/emission_voxels.vxz, <uuid>/pbr_voxels.vxz
data/train/multiview/multiview-00007.tar <uuid>/multiview/000_albedo.png ... 005_alpha.png, transforms.json
data/train/thumbnail/thumbnail-00007.tar <uuid>/thumbnail.png
metadata.parquet gives each shape's shard; there are 156 tars in all. Each atlas.npz is a
deflate-compressed .npz, which np.load reads as usual.
# the root files, then one kind of file for every split
hf download 3dlg-hcvc/LightgenBench README.md splits.json metadata.parquet checksums.sha256 assets/teaser.jpg --repo-type dataset --local-dir lightgenbench
hf download 3dlg-hcvc/LightgenBench --repo-type dataset --include "data/*/voxels/*" --local-dir lightgenbench
# or everything
hf download 3dlg-hcvc/LightgenBench --repo-type dataset --local-dir lightgenbench
# check, then unpack every tar in place: lightgenbench/<uuid>/<file>, next to splits.json
cd lightgenbench && sha256sum -c --ignore-missing checksums.sha256
for t in data/*/*/*.tar; do tar -xf "$t"; done # rm -r data/ afterwards to free the tar space
Dataset structure
After unpacking, every shape is one directory named by its TexVerse uuid, and splits.json
lists the uuids of each split in train/val/test:
<uuid>/
atlas.npz
emission_voxels.vxz
pbr_voxels.vxz
multiview/ 00N_{albedo,mr,normal,pos,emission,alpha}.png (N = 0..5), transforms.json
thumbnail.png
Splits
| split | shapes |
|---|---|
| train | 36,426 |
| val | 200 |
| test | 200 |
Val and test hold 200 shapes each, drawn category-stratified at random; train is every other released shape.
The validation split picks checkpoints; the test set produces published numbers. Read a split
as json.load(open("splits.json"))["train"] and a shape's files as lightgenbench/<uuid>/<file>.
Preprocessing
Every representation is built from the .glb file, normalized to [−1, 1]. Emission is the material's emissive texture, or its emissive factor as a color when it has no texture.
Representations
atlas.npz
The UV atlas of one shape: a single .npz holding eight 512×512 maps over the same UV layout, each stored as an array whose dtype and channel count are listed below. color and emission_color hold linear RGB values.
| key | dtype | shape | content |
|---|---|---|---|
occupancy |
bool | 512×512×1 | texel covered by the UV layout |
position |
uint16 | 512×512×3 | position in [−1, 1] frame |
objnormal |
uint16 | 512×512×3 | object-space normal |
color |
uint8 | 512×512×3 | base color |
metal |
uint8 | 512×512×1 | metallic |
rough |
uint8 | 512×512×1 | roughness |
emission_color |
uint8 | 512×512×3 | emission |
alpha |
uint8 | 512×512×1 | opacity |
emission_voxels.vxz, pbr_voxels.vxz
Sparse voxels on a 256³ grid over [−0.5, 0.5]³, in the O-Voxel format of
TRELLIS.2, whose o_voxel package reads them.
o_voxel.io.read_vxz(path) returns: an int32 tensor of shape N×3
holding each stored voxel's grid index (0–255 on each axis), where N is the number of voxels stored
for that shape, and a dict of per-voxel attributes, each a uint8 tensor with one row per voxel. emissive and
base_color are linear RGB. The two files carry different attributes over the same list of voxels
in the same order. Attributes:
| file | attribute | dtype | shape |
|---|---|---|---|
emission_voxels.vxz |
emissive |
uint8 | N×3 |
pbr_voxels.vxz |
base_color |
uint8 | N×3 |
metallic, roughness, alpha |
uint8 | N×1 |
multiview/
Six orthographic 512×512 views (front, left, back, right, top, bottom), rendered with the six fixed
cameras of Hunyuan3D-2.1's
training example,
each with six maps: albedo, mr (metallic-roughness), normal, pos,
emission, alpha. The material maps (albedo, mr, emission, alpha) hold linear bytes;
normal and pos are geometry maps.
The object mask is mr red channel == 255.
transforms.json holds the six camera frames.
thumbnail.png
The TexVerse preview images: 36,824 hold JPEG data and 2 hold PNG data. 35,304 are 1920×1080 RGB; the other 1,522 are smaller, down to 256×144, and 277 of those are grayscale.
License
Every shape keeps the license of its source model on Sketchfab (via TexVerse); metadata.parquet
gives each shape's license, author and source_url. Credit the authors and filter on the
license column for your use: NonCommercial licenses allow non-commercial use only, ShareAlike
licenses require the same license on derived work, and NoDerivs licenses do not allow sharing
adapted material.
- CC BY: 34,319
- CC BY-NC: 1,341
- CC BY-NC-SA: 459
- CC BY-NC-ND: 381
- CC BY-SA: 264
- CC BY-ND: 49
- CC0: 13
BibTeX
@inproceedings{lightgenbench2026,
title = {LightGenBench: A Benchmark for 3D Emission Generation},
author = {},
year = {2026}
}