VAST-AI TripoSG integration notice

Portions of the rectified-flow transformer and shape-VAE decoder architecture,
image preprocessing, sampling equations, and hierarchical surface extraction in
this family are modified from:

  VAST-AI-Research/TripoSG
  https://github.com/VAST-AI-Research/TripoSG
  revision fc5c40990181e2a756c4e0b1c2f4d6b5202faf8c

Those portions are provided under the accompanying MIT License:

  MIT License
  Copyright (c) 2025 VAST-AI-Research and contributors.

All ported source files carry a prominent modification notice. Independently
written diffusers-3d package glue remains under the package Apache-2.0 license.

The upstream transformer file states that it is based on Tencent HunyuanDiT.
The upstream NOTICE reads:

  This software contains code derived from HunyuanDiT
  (https://github.com/Tencent/HunyuanDiT). Notice: Tencent Hunyuan is licensed
  under the Tencent Hunyuan Community License Agreement, Copyright © 2024
  Tencent. All Rights Reserved. The trademark rights of “Tencent Hunyuan” are
  owned by Tencent or its affiliate.

This family implements the TripoSG transformer architecture with Diffusers
building blocks (Apache-2.0). Whether that architecture's HunyuanDiT
derivation carries Tencent Hunyuan Community License obligations for this code
has not been determined.

Not included:

- the FlashVDM decoder, its attention processor, and flash_extract_geometry,
  which upstream distributes under the Tencent Hunyuan FlashVDM Community
  License Agreement (triposg/LICENSE upstream);
- diso dual marching cubes (CC BY-NC 4.0);
- the briaai/RMBG-1.4 background remover (bria-rmbg-1.4 license).

Weights are not redistributed. The VAST-AI/TripoSG model card declares the MIT
license; its DINOv2-L image encoder derives from facebook/dinov2-large
(Apache-2.0). Converted checkpoints keep their own licenses.

No affiliation, sponsorship, or endorsement by VAST-AI-Research, Tripo,
Tencent, Meta, or BRIA AI is claimed.