NFF to STEP Converter
FileFlip converts NFF to STEP 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 an NFF file to STEP?#
- Drop your NFF 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 STEP 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 STEP file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting NFF to STEP lose quality?#
Not in the sense of pixels or samples. Converting NFF to STEP rebuilds the file in STEP's own model rather than re-encoding it, so everything STEP 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 NFF files online?#
Yes, because nothing is uploaded. FileFlip converts NFF 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 NFF to STEP actually does to the file#
Converting NFF to STEP 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 skeleton and animation.
| Engine | Assimp |
|---|---|
| Conversion path | One step: NFF → STEP |
| 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 | Sometimes | Survives for some files and not others. |
| Textures | Sometimes | Survives for some files and not others. |
| Skeleton and animation | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- if the source carries a skeleton or animation, this target has no place to store it
What is an NFF file?#
An NFF file is plain text written to Eric Haines' Neutral File Format, first drafted on October 3, 1988 as part of the Standard Procedural Databases project, listing a viewpoint, lights, a background colour and a handful of primitives like spheres, cones and polygons with one letter code starting each line.
Use NFF only when working with an existing ray-tracing benchmark scene or legacy renderer that already expects the format.
Convert NFF to OBJ when its primitives need to become a mesh that a modern 3D application can open.
What is an STEP file?#
An STP file holds a STEP product model in ISO 10303's plain-text exchange syntax, encoding exact boundary-representation solids, surfaces and curves rather than a triangulated mesh.
Use STEP whenever exact CAD geometry, not an approximated mesh, needs to move between two different CAD systems.
Convert a STEP file to a mesh format like STL or OBJ once the model is finished and only needs to be viewed, rendered or 3D printed rather than edited as a solid.
NFF to STEP questions people ask#
What is an NFF file?
An NFF file is a plain-text scene description in Eric Haines' Neutral File Format, listing a camera, lights, a background colour and simple primitives like spheres, cones and polygons. Haines created it in 1988 as part of the Standard Procedural Databases project, a set of test scenes meant to let different ray tracers be compared on identical input.
What software can open NFF files?
NFF has no mainstream viewer today; support is limited to older ray tracers and a handful of 3D libraries, such as Assimp, that kept a reader for benchmark and archival purposes. A general-purpose 3D application is unlikely to open one directly.
Does NFF support textures or materials?
No, an NFF surface is described with only a fill colour, a diffuse and specular coefficient, shininess, transmittance and index of refraction, with no texture mapping at all. That simplicity is what made it easy for different renderers to implement consistently.
What does STP stand for?
STP is the file extension for STEP, the Standard for the Exchange of Product model data, formally ISO 10303. It's the neutral format mechanical CAD systems use to hand solid models to each other.