SolidSKeleton

July 4, 2026 ยท View on GitHub

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Reference implementations are not part of the SSK specification

SolidSKeleton is an open geometry data format for lightweight solid (CSG) modeling, designed to stay expressive without excessive structural or class overhead.

SolidSKeleton is built around two main concepts: user-defined sets of points, or a single point, with properties that create or remove material; hence Solid(material)Skeleton(Points).

A SolidSKeleton document .ssk/.sskb describes geometry as a list of pieces ordered by id for interpretation. Each piece either generates material or subtracts from generated material. Pieces are either path-defined (two or more points, swept cross-section) or point-defined (one point, volumetric form).

What does SolidSKeleton bring to the table?

The format is lightly typed and enforces strict structural constraints, allowing humans and Large Language Models to generate geometry deterministically while minimizing heuristic behavior. Because the architecture relies on piece referencing, the resulting file sizes are incredibly small. This makes the compiled .sskb format highly efficient for data streaming, allowing thousands of generated objects to be transferred in just a few kilobytes. The simple syntax enables a lightweight local tessellation layer to translate these objects in milliseconds.

Project Status

  • Status: Current
  • Version: 1.0
  • Author: Rogier Goossen

As of 29-6-2026, the SolidSKeleton SPEC has been released under the stable v1.0 version. Implementations will continue under the v1.* version.

Specifications

Read in order:

  1. spec/geometry/SPEC.md: geometry model and semantics
  2. spec/format/ssk/SPEC.md: .ssk text encoding
  3. spec/format/sskb/SPEC.md: .sskb binary encoding

Packages

implementation/packages/.

The packages are API wrappers over the rust core @implementation/core/ and in langauge mesh to ssk estimator.

Core

implementation/core/.

The rust core is dependents on Manifold. The core is reference implimentation and is based on the SolidSKeleton SPEC.

Examples

examples/.

The examples includes screenshots, ssk, sskb and glb files.

License

LICENSE.

And the full license files can be found at /licenses.

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