PK3 to STEP Converter
FileFlip converts PK3 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 a PK3 file to STEP?#
- Drop your PK3 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 PK3 to STEP lose quality?#
Not in the sense of pixels or samples. Converting PK3 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 PK3 files online?#
Yes, because nothing is uploaded. FileFlip converts PK3 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 PK3 to STEP actually does to the file#
Converting PK3 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: PK3 → 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 a PK3 file?#
A PK3 file is a Quake III Arena game archive, an ordinary ZIP file renamed with a .pk3 extension so id Tech 3's engine loads its maps, models, textures and sounds straight out of the package.
Use PK3 to package and distribute a Quake III Arena map or mod's assets as one file that the engine loads directly.
Convert a PK3 into its individual files when the goal is to reuse a specific model, texture or sound rather than run the package inside the game.
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.
PK3 to STEP questions people ask#
What is a PK3 file?
A PK3 file is a Quake III Arena game archive, structurally just a ZIP file with the extension changed to .pk3 so id Tech 3's engine recognizes and loads it directly. It typically bundles a mod or map pack's BSP levels, MD3 models, textures and sounds together.
Can I open a PK3 file with a normal ZIP tool?
Yes. A PK3 file is an ordinary ZIP archive under a different extension, so any ZIP tool, or simply renaming the file to end in .zip, opens it and lists its contents.
Why does Quake III use PK3 instead of loose files?
Packing a mod or map's files into a single PK3 keeps them organized in the exact folder structure the engine expects and lets it read straight out of the archive without unpacking to disk first, which made distributing and installing custom content much simpler than shipping loose files.
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.