Free online STEP, STL, DXF and DWG viewer. Open a file, spin it around, check dimensions, measure between points and print a drawing sheet — 100% in your browser, nothing is uploaded. CDI Motorsport.
Drop your CAD file hereor click to browse · STEPSTPSTLDXFDWGIGES · nothing leaves your computer
STEP and IGES carry their own units and are converted to millimetres automatically. STL, DXF and DWG files are unit-less — if the dimensions look 25× too small, switch to inches.
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Print drawing
Third-angle projection with a CDI Motorsport title block, overall dimensions and scale. Choose Actual size / 100% in your print dialog for the stated scale to be true — handy for printing 1:1 templates from DXF profiles to check against a part on the bench.
Need this made?
CDI Motorsport CNC cuts, folds, tube-copes and fabricates from exactly these files. Send us the details of what you just opened and we will quote it — laser/plasma profiles from DXF/DWG, formed sheetmetal, machined parts and full fabrication from STEP.
About this viewer
Which files can I open?
STEP (.step/.stp, AP203/AP214/AP242), IGES (.iges/.igs), STL (binary or ASCII), DXF (all common entities — lines, polylines with arcs, circles, arcs, ellipses, splines, blocks, dimensions and text) and DWG (R13 through 2018). Solid models are shown shaded with feature edges; DXF/DWG are shown as a 2D drawing with layers.
Is my file uploaded anywhere?
No. Everything runs inside your browser. The STEP and DWG readers are open-source engines (OpenCascade and LibreDWG) compiled to WebAssembly and downloaded from a CDN the first time you use them — your file itself never leaves your computer.
Why does STEP or DWG take a moment to open the first time?
The STEP reader is about 8 MB and the DWG reader about 10 MB. They download once and are cached by your browser; after that files open in a second or two. STL and DXF open instantly.
How accurate is the measurement?
Measurements snap to model vertices (mesh corners, line endpoints, arc ends) and report straight-line distance plus the X/Y/Z components in millimetres. STEP geometry is exact; STL and tessellated curves are only as accurate as the mesh.
Can I print at true scale?
Yes. Pick 1:1 (or any standard scale) and choose 100% / actual size in the print dialog. DXF/DWG drawings print as crisp vector line-work; 3D models print as shaded views with edges. The title block states the scale used.
Where is the origin and which way is up?
Models are shown exactly where they sit in the file — the grid is the XY plane, Z is up (the usual CAD convention). Front looks along +Y, Right looks along −X, Top looks down −Z, and the views on the printed sheet follow third-angle projection (AS 1100 / ISO).
Free Online CAD Viewer: open STEP, STL, DXF and DWG without a CAD licence
Open STEP, STP, IGES, STL, DXF and DWG files right in your browser. Rotate and measure them, take section cuts, and print third-angle drawing sheets to scale. It's free, you don't need an account, and nothing is uploaded: everything runs on your own computer.
What it saves you
Software cost: no CAD licence just to look at a file a customer or supplier has sent you.
Time: drop in a file and check it in seconds, with no installing, converting or emailing back and forth to ask for a PDF.
Costly mistakes: measure and check a part, or print a DXF profile 1:1 to hold against the job, before anything gets cut.
Privacy: your files never leave your computer, so customer and in-house designs stay private.
How it works
Drop your file onto the viewer, or click to browse. STEP and IGES units are read automatically; for STL, DXF and DWG, pick the units the file was drawn in.
Spin, zoom and switch between standard views. Turn on edges, wireframe, a bounding box with overall dimensions, or a section cut. DXF and DWG layers can be switched on and off.
Use Measure to snap between points, save a PNG snapshot, or print a third-angle drawing sheet at a standard scale on A4, A3 or Letter.
Frequently asked questions
How do I open a STEP file without SolidWorks or Fusion?
Drop the .step or .stp file into this viewer. It opens in your browser, shaded with feature edges, and you can rotate, measure and section it with no CAD software installed.
Can I open DWG files for free?
Yes. DWG files from R13 through 2018 open as a 2D drawing with layers, and you can print them as vector line-work at true scale.
Can I check a DXF before sending it for laser or waterjet cutting?
Yes. Open the DXF, check the dimensions and layers, and print it 1:1 to check against the real part. When it's right, send it to us to cut.
Is my file uploaded?
No. The file is read and displayed entirely in your browser. The STEP and DWG readers download once the first time you use them, then open files in a second or two.
Is it free?
Yes. It's free to use and you don't need to sign up.
