LightGenBench (preliminary)

This repo holds every shape of the released dataset described under "The data", packed as tar shards per representation.

Repository layout

README.md          this card
splits.json        the split of each shape
metadata.parquet   one row per shape: uuid, split, shard, category, license, author, author_username, source_url
checksums.sha256   sha256 of every file except this card
data/              <split>/<representation>/<representation>-<shard>.tar, shard in 5 digits (data/train/voxels/voxels-00000.tar)

Each split's uuids are sorted and cut into shards of 1,000 shapes. A tar holds one representation's files for one shard (atlas: atlas.npz; voxels: the two .vxz files; multiview: multiview/; thumbnail: thumbnail.png) at paths <uuid>/<file>, as in the tree under "The data". Shard k holds the same shapes in every representation. The atlas.npz files here are stored compressed; the arrays are the same and np.load reads them the same way.

Download and unpack

# the root files, then one representation for every split
hf download 3dlg-hcvc/LightgenBench README.md splits.json metadata.parquet checksums.sha256 --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 and splits.json into ../root
cd lightgenbench && sha256sum -c --ignore-missing checksums.sha256
mkdir -p ../root && for t in data/*/*/*.tar; do tar -xf "$t" -C ../root; done && cp splits.json ../root/

The data

Emissive 3D shapes from TexVerse with their material and emission maps in three representations: a UV atlas, sparse voxels, and six rendered views. One directory per shape, named by its TexVerse uuid.

README.md
splits.json          {"train": [uuid, ...], "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 are 200 shapes each. Every shape of the earlier paper's validation split and test set that passed stays in val and test respectively (170 and 178); the rest were drawn category-stratified at random with seed 42. Train is every other released shape. 232 pass shapes were left out of train: 91 outside the bake pass (they failed the bake's alignment gate, so they have no views) and 141 without a thumbnail. None were in val or test.

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 <root>/<uuid>/<file>.

atlas.npz

512×512 maps. Material values are linear, stored as clip(v, 0, 1) · 255.

key	dtype	shape	content
occupancy	bool	512×512×1	texel covered by the UV layout
position	uint16	512×512×3	position in the canonical [−1, 1] frame, stored as (v · 0.5 + 0.5) · 65535
objnormal	uint16	512×512×3	object-space normal, same encoding
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, both files on the same voxels. Read with o_voxel.io.read_vxz(path), which returns the coordinates (int32, N×3) and a dict of attributes. The voxel frame and the atlas frame hold the same normalized object, centered the same way; the voxel frame is half the scale (a point p in the atlas frame is at p / 2 in the voxel frame). 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, right, back, left, top, bottom; the Hunyuan3D-Paint training cameras), 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 in Hunyuan3D-Paint's encoding. Outside the silhouette every map is gray 127. The object mask is mr red channel == 255 (alpha is material opacity, not the mask). transforms.json holds the six camera frames.

thumbnail.png

The TexVerse preview image as shipped, under a .png name: 36,824 hold JPEG data and 2 hold PNG data. 35,304 (both PNG among them) are 1920×1080 RGB; the other 1,522 are smaller, down to 256×144, and 277 of those are grayscale. Decode by content (PIL does) and convert to RGB: Image.open(path).convert("RGB").

Emission rule

A material's emission is its emissive texture alone (sRGB-decoded to linear) when it has one, else its emissive factor color, else black. emissiveFactor does not scale a texture, and KHR_materials_emissive_strength is not applied.

How the shapes were selected

1. Metadata filtering of the TexVerse GLBs: 83,124 pass (declared emission and a full PBR material; 103,762 declare emission).
2. Heuristic filtering: the zero-emission check passes 77,569; the copy check (emission is not a copy of the base color) passes 73,432.
3. Duplicate check: 69,942 (copies with the same geometry, albedo and emission removed).
4. Data preparation: atlas and voxels for 70,996 of the 73,432, views for 70,988.
5. VLM filtering: 37,058 pass of the 69,942 (a vision-language model judges eight review images per shape; shapes whose baked emission map is all zero are rejected).
6. Released: 36,826, the pass shapes with every file above.

Licenses

Every shape keeps the license of its source model on Sketchfab (via TexVerse). Credit the authors. NoDerivs licenses do not allow sharing adapted material, and NonCommercial licenses allow non-commercial use only; a public release must filter on the license column.

license	shapes
CC Attribution	34,319
CC Attribution-NonCommercial	1,341
CC Attribution-NonCommercial-ShareAlike	459
CC Attribution-NonCommercial-NoDerivs	381
CC Attribution-ShareAlike	264
CC Attribution-NoDerivs	49
CC0 Public Domain	13