B3D to STL Converter
FileFlip converts B3D to STL entirely inside your browser, using Assimp compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a B3D file to STL?#
- Drop your B3D file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to STL and the conversion starts on its own. FileFlip downloads 11.2 MB of WebAssembly the first time and nothing after that, then runs Assimp on your own machine.
- Save the STL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting B3D to STL lose quality?#
Not in the sense of pixels or samples. Converting B3D to STL rebuilds the file in STL's own model rather than re-encoding it, so everything STL can represent comes through exactly and anything it cannot has to be dropped. Expect the geometry to be exact, and anything the target has no place for, such as a rig, to be left behind.
Is it safe to convert B3D files online?#
Yes, because nothing is uploaded. FileFlip converts B3D files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What B3D to STL actually does to the file#
Converting B3D to STL runs on Assimp, downloads 11.2 MB of WebAssembly the first time and nothing after that, rebuilds the file in the target's own model, and drops materials, textures and skeleton and animation.
| Engine | Assimp |
|---|---|
| Conversion path | One step: B3D → STL |
| Downloaded to your browser | 11.2 MB, once, then cached by your browser |
| Quality | Rebuilt in the target's model |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Materials | Dropped | The target format has nowhere to put it. |
| Textures | Dropped | The target format has nowhere to put it. |
| Skeleton and animation | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the target stores triangles and nothing else, so materials, colours, and texture coordinates have nowhere to go
- if the source carries a skeleton or animation, this target has no place to store it
What is a B3D file?#
A B3D file is the binary chunk-based model format of Blitz3D, storing meshes, textures, materials, a bone hierarchy and keyframe animation for games written in that BASIC-derived language.
Use B3D when working directly in Blitz3D or maintaining an existing Blitz3D game's asset pipeline.
Convert B3D to glTF or FBX to bring a rigged, animated model into a modern engine, since Blitz3D itself hasn't been actively developed in years.
What is an STL file?#
An STL file is a triangle mesh created by 3D Systems in 1987 for its stereolithography 3D printers, storing nothing but a flat list of triangle facets and their normals, with no colour, material or unit of measurement attached.
Use STL when the only destination is a 3D printer's slicer, which is all the format was designed to feed.
Convert STL to 3MF when colour, material or unit information needs to travel with the geometry, since STL has nowhere to put any of it.
B3D to STL questions people ask#
What is a B3D file?
A B3D file is a 3D model in Blitz3D's native binary format, storing a mesh along with its textures, materials, bone hierarchy and keyframe animation. Blitz3D was a BASIC-derived language and engine popular for small, hobbyist games in the early 2000s.
Does a B3D file support animated characters?
Yes. A B3D file can store a full bone hierarchy with vertex weights and keyframed position, scale and rotation data, which is more than many game formats from the same era managed.
What software opens B3D files?
Blitz3D itself is the primary application, since the format was built specifically for it. Blitz3D and BlitzPlus were released as open-source software in 2014, which is why later third-party tools have been able to add B3D support.
What is an STL file used for?
An STL file is the standard input for 3D printer slicing software, storing a model's surface as a list of triangles with nothing else attached. Slicers use it to work out where to lay down material layer by layer.