Spark

Spark is an open source 3D Gaussian Splatting renderer for three.js, built by World Labs and released under the MIT licence. It launched as Forge in June 2025 and was renamed Spark later that month after a clash with another graphics company using the Forge name, moving to the @sparkjsdev/spark package on npm and the sparkjs.dev domain.

Spark plugs into the three.js rendering pipeline, so splats and meshes share one scene and several splat objects sort together correctly. It reads PLY including compressed PLY, SPZ up to version 4, SPLAT, KSPLAT and SOG files, can render several viewpoints at once, and treats every splat as editable, with real time colour editing, displacement, skeletal animation and a shader graph that creates and edits splats on the GPU.

Spark targets WebGL2 rather than WebGPU, which its developers put at 98 percent or more of devices, low powered phones included. It needs three.js r180 or later and installs from npm or loads as an ES module from a CDN, and its level of detail traversal runs in Rust compiled to WebAssembly.

Spark 2.0 arrived on April 14, 2026 with a streamable level of detail system. Each scene becomes a tree in which every parent is a merged, lower resolution version of its children, and Spark picks a slice through that tree for the current viewpoint within a fixed splat budget, such as 500,000 splats on a phone or 2.5 million on desktop. The .RAD format that shipped with it stores splats in 64K chunks that can be fetched by byte offset, so scenes of more than 100 million splats stream into a browser.

Later releases refine that system. Spark 2.2.0 brought faster level of detail traversal and Rust decoders in September 2026, and Spark 2.3.0 fixed on demand rendering for paged level of detail at the end of that month, adding credentialed and custom header loading and SPZ export of extended splats through writeSpz. Spark 2.4.0, published to npm on October 20, 2026, added SPZ v4 reading, moved paged level of detail loading behind a PagedSplatsFetcher interface, so data can come from an in-memory file, a URL or a custom fetcher passed through the new fetchSource option, and switched RAD and SPZ compression to the flate2 library, which its developers credit with about 50 percent faster RAD compression and about 20 percent faster decoding.

GitHub recognised Spark among the most influential open source projects showcased at GitHub Universe 2025, and other tools build on it, such as Andres Romero's splattie-widget, which drops a rigged splat into a web page with a single custom element. Voxel51's FiftyOne dataset toolkit renders Gaussian splats in its 3D viewer through Spark from FiftyOne 1.21.0, covering PLY, SPZ, SPLAT, KSPLAT, SOG and RAD files. AMD signed an agreement to acquire World Labs in September 2026, with closing expected by the end of the year.