**trellis.cpp** is a standalone **C++/GGML** reimplementation of Microsoft's **TRELLIS.2-4B** image-to-3D pipeline. It carries the whole chain — background removal, image conditioning, three flow transformers, the VAE decoders, mesh extraction and UV-textured GLB export — with **no Python at runtime**. The repository is **MIT**-licensed and has drawn **261 stars and 24 forks** since its **28 June 2026** creation. The pipeline mirrors the reference implementation stage for stage. A **BiRefNet** or RMBG matte cuts the subject out, **DINOv3 ViT-L/16** turns the RGBA cutout into patch tokens, and three 1.3B flow DiTs run in sequence: a dense **sparse-structure** transformer at 16³ that decodes to a 64³ occupancy grid, a sparse **Shape-SLAT** transformer whose FlexiDualGrid decoder feeds FlexiCubes mesh extraction, and a sparse **Texture-SLAT** transformer that emits six-channel PBR values per voxel. Every one of those blocks runs on GGML, so the same source tree builds against **CUDA, ROCm, Vulkan and CPU**. The postprocess is where a port usually diverges, and this one does not. The raw dual-grid mesh is welded and hole-filled, remeshed with **narrow-band UDF dual contouring** into a single manifold, quadric-simplified to a face budget (300K at res-1024), cluster-merged with the reference's normal-cone pass, unwrapped with stock **xatlas**, baked per texel by trilinear sampling of the voxel PBR volume with a BVH closest-point snap, gutter-filled with a Telea inpaint port, and written out as a **GLB with lossy-WebP textures** via `EXT_texture_webp`. The project documents this op-by-op against the reference in its spec and divergence-matrix docs and states parity with the reference CUDA postprocess on identical inputs. Two front ends sit on top of the same engine. **`trellis-server`** stays resident so Vulkan is not re-initialised per request, exposing `GET /health` and a multipart `POST /generate` that returns `model/gltf-binary`; launch flags set defaults and each request can override seed, resolution and background-removal mode. **Trellis Studio** is a Tauri desktop app installed by one `curl | bash` (or `irm | iex` on Windows) that auto-detects the GPU runtime, pulls the matching server build plus roughly **16.5 GB of weights**, supervises the server, and keeps every result in a local IndexedDB gallery. The project also serves as the `trellis` backend of **Lemonade**, and can be driven end-to-end from a text prompt by pairing it with **stable-diffusion.cpp** for the input image. Release **v0.6.0** landed on **19 August 2026** and is mostly a reliability release. It fixes the severe holes and corrupted geometry the 0.5.4 CUDA build produced at high resolution — FlashAttention values are power-of-two scaled around the tensor-core path so large Shape-SLAT activations stay finite, and the pinned GGML revision uses 64-bit mask strides for attention masks above 2 GiB. BiRefNet now evaluates its final high-resolution convolutions in bounded-height stripes and resizes the matte back to the source dimensions, so non-square inputs stop being stretched. Separate **`cuda12` packages** built with CUDA 12.9 restore Pascal and Volta support (compute capability 6.0, 6.1 and 7.0, cards such as the Tesla P100), with the installers picking the legacy runtime automatically. CPU execution now uses all available cores by default: a contributed 20-core benchmark moved the sparse-structure flow stage from **305 s/step to 118 s/step**, a 2.6x improvement on that machine. Worth knowing before you commit: the CPU path is described by the project itself as very slow and RAM-hungry — `--require-gpu` exists precisely to fail rather than silently fall back — and the ROCm backend is still labelled experimental in the release assets.