Lux3D RMBG-1.4 Canonical Weights

This repository contains the canonicalized safetensors export of BRIA RMBG-1.4 used by the Lux3D TripoSG preprocessing runtime.

Model Details

• Model family: rmbg (auxiliary package, not a Lux3D output family)
• Architecture: BriaRMBG / IS-Net
• Canonical file: model.safetensors (176,381,952 bytes)
• Tensor count: 798 (686 F32 parameters + 112 int64 num_batches_tracked buffers)
• SHA-256: fb54c81529b99336009dd76de98e11491fe85a956c937814e8178f17c04891aa
• Source checkpoint SHA-256: 46ef7fe46f2ae284d8f1aaa24bfa5fca5ef25a34e2c7caa890a0029eb100e87f
• Primary runtime target: Lux3D TripoSG preprocessing
• Typical output: single-channel foreground mask

RMBG-1.4 is the background-removal network used by the reference TripoSG scripts/image_process.py when an input image has no valid alpha channel. Lux3D runs the same path:

1. cap the longest source side at 2000 pixels;
2. resize RGB to 1024x1024 with torchvision-compatible bilinear antialiasing;
3. normalize with mean [0.5, 0.5, 0.5] and std [1.0, 1.0, 1.0];
4. run BriaRMBG and take the first sigmoid side output;
5. resize the mask back, min-max normalize, quantize to uint8, and apply Otsu thresholding;
6. remove 8-connected components smaller than 200 pixels;
7. composite the largest foreground component over white and pad it to a square with 10% padding.

Why This Package Is Separate

TripoSG is MIT licensed, while RMBG-1.4 is source-available for non-commercial use only under the BRIA RMBG 1.4 license. Keeping RMBG in a separate canonical package makes the license boundary explicit and lets the TripoSG package remain MIT.

RMBG is not part of oxide-lab/TripoSG and must be obtained separately.

Included Files

• model.safetensors — canonical F32/int64 weights, names unchanged from the upstream checkpoint
• resolved_config.json — architecture and preprocessing metadata
• manifest.json — provenance, source checksums, tensor count, and raw-file list
• checksums.json — SHA-256 and size for every file in this package

Usage With Lux3D

Pass the package to the TripoSG CLI:

cargo run -p lux3d-cli --features cuda -- run triposg `
  --model-path <canonical-triposg-dir> `
  --rmbg-model-path <canonical-rmbg-dir> `
  --source <input-image> `
  --output <output-file.obj>

If --rmbg-model-path is omitted, the CLI looks for a sibling rmbg-1.4 directory next to an explicit --model-path. The HTTP server accepts --rmbg-model-path or LUX3D_RMBG_MODEL_PATH and performs the same sibling discovery.

The package is only needed when the input has no valid alpha channel. RGBA inputs with a usable alpha channel take the native alpha path and never load these weights.

Provenance

• Upstream source model: briaai/RMBG-1.4
• Reference architecture: xuebinqin/DIS (IS-Net), as modified by BRIA
• Canonicalization flow: tools/python_baseline/normalize_weights.py
• Raw source files: model.safetensors, config.json, preprocessor_config.json

The upstream model.safetensors is copied tensor-for-tensor; no values or names are modified. BatchNorm num_batches_tracked buffers remain int64.

Validation

The Lux3D Rust/Candle implementation was validated against the reference PyTorch execution of TripoSG's exact preprocessing path on the RGB golden sample:

Check	Result
BriaRMBG sigmoid max abs delta	1.311e-6
preprocess uint8 pixel_values	exact
normalized pixel_values max abs delta	2.384e-7

The reference baseline and the Rust runtime both reproduce the upstream load_image output exactly at the uint8 conditioning stage.

Limitations

• License: RMBG-1.4 is source-available for non-commercial use. Commercial use requires a separate agreement with BRIA. See LICENSE.md and the upstream license link.
• The model is implemented for CPU, CUDA, Vulkan, and WGPU; Metal is build-supported but untested in this repository.
• Inference is F32-only in the current Lux3D runtime.
• The canonical package contains no trained weights beyond the upstream checkpoint and no upstream demo/training stack.
• Lux3D does not redistribute the source repository; only the canonicalized weights and metadata are included here.

License

• Upstream model page: briaai/RMBG-1.4
• License: BRIA RMBG 1.4
• The model is released under a Creative Commons license for non-commercial use.
• Commercial use is subject to a commercial agreement with BRIA: https://go.bria.ai/3B4Asxv

This package does not grant any rights beyond the upstream license.

Citation

@misc{rmbg14,
  title={BRIA Background Removal v1.4},
  author={{BRIA AI}},
  year={2024},
  howpublished={\url{https://huggingface.co/briaai/RMBG-1.4}}
}