Convert PLN to STEP (Free)
Also converts STL, OBJ, GLB, PLY, USDZ, 3MF from the same file.
Runs in your browser. No upload, no signup, nothing to install.
Also from Innerscene: Circadian Lab, a free lighting calculator for room illuminance, melanopic EML, and glare.
How to convert PLN to STEP
- 1
Open your .pln file
Drag it onto the viewer above, or click "Open a PLN File". Files up to 200 MB open directly; the parse runs in a worker so the page stays responsive.
- 2
Pick STEP AP214 in the Export menu
Click Export in the toolbar, then STEP (.step).
- 3
Download
The .step is written in the browser and saved straight to your downloads folder. No queue, no email, no watermark.
What survives the conversion
A file conversion is a translation, and formats do not carry the same things. Here is exactly what moves from PLN into STEP, and what does not.
| Geometry | Reduced | The triangles become a faceted B-rep: one planar face per triangle inside a closed shell. CAD reads it as real solid geometry with true units, but the faces stay faceted, they do not become NURBS surfaces. |
|---|---|---|
| Colors and materials | N/A | Neither format carries color, so there is nothing to lose. |
| Layers and structure | Dropped | STEP is a single flat body with no layers or named parts. Everything merges into one object. If you need the structure, export to GLB, OBJ, DXF instead. |
| Units and scale | Kept | STEP stores an explicit unit, so the model opens at true size without rescaling. |
What the STEP writer emits: ISO 10303-21 AP214, each mesh written as a faceted B-rep: one planar face per triangle inside a closed shell, in millimeters under an explicit SI unit. Exact for polyhedral shapes, a faithful tessellation for curved ones.
The source: Graphisoft Archicad (.pln, .pla)
Supported Archicad building geometry: walls with door and window openings cut through them, slabs, pitched roofs, zones, beams, columns, morphs, meshes and terrain. PLN and PLA files from Archicad 25, 27 and 29 have been tested.
The target: STEP AP214 (.step)
The neutral CAD exchange format every mechanical package imports.
Opens in: SolidWorks, Fusion 360, Inventor, CATIA, NX, Creo, FreeCAD, Onshape.
Your file never leaves your computer
Both the PLN parser and the STEP writer are JavaScript and WebAssembly running in your own browser tab. There is no upload step, no server-side conversion queue, and no copy of your file anywhere but your machine. That matters for drawings under NDA, for client work, and for anything you would not email to a stranger.
Free to Use, No Signup
There are no accounts and no watermarks on this converter. If it saved you time, the one thing we ask is a mention: a post, a link from your blog or course page, or a reply to someone asking how to open a file.
Share it
Made something reusable? Add it to the Free Parts Library. Writing about it? Copy a link, badge or citation. Send us your post and we’ll feature it with a link to your site.
Hear about new formats
Occasional emails when the viewer learns a new format or gets a new tool.
Frequently asked questions
▶Is this PLN to STEP converter free?
Yes. No signup, no watermark, no per-file limit and no paid tier. Innerscene.
▶Is my PLN file uploaded anywhere?
No. The file is read with the browser file API and converted in the same tab. Nothing is sent to a server unless you explicitly click Share, which is a separate, opt-in feature.
▶Will my colors and materials survive the STEP export?
Neither format carries color, so there is nothing to lose.
▶Do layers and named parts carry into the STEP file?
STEP is a single flat body with no layers or named parts. Everything merges into one object. If you need the structure, export to GLB, OBJ, DXF instead.
▶Will the STEP open at the right size?
STEP stores an explicit unit, so the model opens at true size without rescaling.
▶How large a PLN file can I convert?
Up to 200 MB, and the ceiling adapts to how much memory your device reports. The conversion runs on your own hardware, so a desktop with plenty of RAM will handle more than a phone.
▶Can I convert STEP back to PLN?
Not here. We read PLN and write STEP, but not the reverse. the universal 3D viewer
▶Which browsers does it work in?
Chrome, Edge, Firefox and Safari, on Windows, macOS, Linux, iOS and Android. No plugin and no extension.
Convert PLN to something else
Convert something else to STEP
Or start from the universal 3D viewer.