STEP · STP · CAD Viewer
Online STEP File Viewer
Drop a .step or .stp file to see it in 3D with its original part colors, browse the assembly tree, hide or isolate parts, cut a section to look inside, and measure distances. Free, no CAD software, and the file never leaves your browser.
No STEP handy?
About the STEP viewer
- Opens STEP (AP203 / AP214 / AP242) and the .stp extension — the neutral CAD exchange format written by SolidWorks, Fusion 360, CATIA, Inventor and Onshape.
- The B-rep solid is tessellated in your browser by an OpenCascade WASM engine, so the first file takes a few seconds to load the engine — after that it's instant.
- Everything runs on your device. There's no upload, no account, and no file-size paywall — useful when the CAD file is under NDA.
- The parts panel mirrors the file's assembly structure (sub-assemblies → parts) with their names; untick a part to hide it or click “only” to isolate it. Part colors from the CAD file are kept.
- Measure: click two points on any surface to get the distance and X/Y/Z offsets in millimeters — files saved in inches are converted on import.
- Section: cut the model along X, Y or Z and drag the plane through it. The cut faces are filled in red so walls, bores and internal parts read as solid, and you can measure across the cut to check a wall thickness.
- It doesn't show the parametric feature history or PMI annotations (GD&T, tolerances), and measuring is point-to-point rather than hole diameters or angles.
- Need the model elsewhere? Convert the STEP to STL, OBJ, GLB, 3MF or PLY below.
Frequently asked questions
- How do I open a STEP file online?
- Drop your .step or .stp file into the box above. It's tessellated and rendered right in the browser — drag to rotate, scroll to zoom. Nothing is uploaded and no CAD software is needed.
- Is this STEP viewer free?
- Yes. Completely free with no signup, no watermark and no file-size limit beyond 200MB. There's no trial and no paid tier.
- What's the difference between .step and .stp?
- Nothing — they're the same ISO 10303 format with two extensions. Older Windows software preferred the three-letter .stp. This viewer accepts both.
- Can I see the parts of a STEP assembly?
- Yes. The File details panel lists the assembly tree from the file — sub-assemblies and parts by name. Untick any part to hide it, or click “only” to isolate a single part, then “show all” to bring everything back.
- Can I measure a STEP file online?
- Yes. Click Measure and pick two points on the model; you get the straight-line distance and the X/Y/Z offsets in millimeters. It's point-to-point measuring on the tessellated surface — enough to check overall sizes and clearances, not a replacement for CAD inspection tools.
- Can I see a cross-section of a STEP file?
- Yes. Click Section, pick the X, Y or Z axis and drag the slider to move the cutting plane; ⇄ keeps the other side. The cut faces are filled in red so you can see wall thickness, bores and how parts sit inside the assembly. Turn on Measure while sectioning and clicks on the red face land exactly on the cut, so you can measure a wall. It's a visual section of the tessellated model, not a 2D drawing — for a DXF of a cut, use STEP to DXF.
- Is my CAD file uploaded to a server?
- No. There is no server and no upload. The file is parsed and rendered entirely on your device, and nothing is stored — which is why it's safe for confidential parts.
- Why does the first STEP file take a few seconds?
- STEP is a B-rep (solid) format, so it has to be converted to triangles before it can be drawn. Flip3D loads an OpenCascade WASM engine once to do that; every file after it opens much faster.
- Can I convert the STEP file to STL for 3D printing?
- Yes. Flip3D converts STEP to STL, OBJ, GLB, 3MF and PLY in the browser. STEP is read-only here (there's no STEP export — mesh formats can't be turned back into real solids), but every mesh export is available. Convert links are by the viewer.