3D File Converters — STL, OBJ, PLY, GLB, GLTF, 3MF
Two questions decide every 3D format conversion: what does each format store, and what gets dropped in the swap. This hub collects all eight converters this site runs — five routes into STL (from GLB, OBJ, PLY, 3MF and GLTF) and three routes back out (to OBJ, PLY and GLB). Every one of them runs entirely in your browser with the same engine: load, inspect in 3D, export. No upload, no account, no daily limit.
The converters
Converting into STL (for printing)
STL is the print shop language: triangles only, no color, no units, every slicer fluent in it. The five conversion routes into STL each drop something different on the way in — GLB and GLTF give up textures, OBJ leaves its materials (.mtl) behind, PLY drops per-vertex color, 3MF loses object colors, units and plate layout. In every case the geometry survives completely, and each converter page spells out exactly what is lost so nothing is a surprise after the fact.
Converting out of STL (for pipelines and viewers)
STL is a dead end for anything that wants more than triangles — no color, no scene, no materials. Converting out to OBJ, PLY or GLB re-wraps the same mesh in a container that other tools speak: OBJ for DCC tools and their .mtl pipeline, PLY for scanning and research software, GLB for browsers, AR and game engines. Nothing is gained visually (STL had nothing to carry), but doors open.
Why these converters are free while the AI tools are not
Honest accounting: format conversion is arithmetic on triangles your own device can do with WebGL, so it costs us nothing to offer and costs you nothing to use — free and unlimited is the honest price. AI image-to-3D reconstruction spends real GPU time on a cloud model, which is why that part of the site runs on a free daily model plus credit packs. Same site, two different cost structures, priced the way each actually works.