Free Online STEP File Viewer
Drop a STEP file and inspect full parametric geometry in your browser. Measure distances, review assemblies, and export to STL — no install, no license.
What is a STEP file?
STEP (Standard for the Exchange of Product Data, ISO 10303) is the universal CAD exchange format. Unlike mesh formats like STL, STEP preserves exact mathematical geometry — NURBS surfaces, solid bodies, assembly hierarchies, and product metadata. It is the standard interchange format for SolidWorks, Fusion 360, CATIA, NX, Creo, and nearly every professional CAD tool.
What you can do with STEP files in CADDaddy
CADDaddy parses STEP files locally using OpenCascade compiled to WebAssembly, so your geometry never leaves your machine. Once loaded, you get full 3D orbit, zoom, and pan controls with 60fps navigation even on complex assemblies.
Instant browser viewing
Open .step and .stp files in seconds. No software install, no plugins, no account required to start.
Assembly inspection
Navigate multi-body assemblies with the component tree. Select, highlight, and isolate individual parts.
Measurement tools
Point-to-point distance measurement with vertex snapping and real-world unit calibration (mm, cm, m, in, ft).
STEP to STL export
Convert STEP to STL for 3D printing or to GLB for web and game engines with one click.
Cross-section inspection
Slice through geometry along any axis to verify internal features, wall thickness, and fit.
Shareable review links
Generate a link so clients or teammates can review the same STEP model without any software.
STEP Viewer FAQ
What is a STEP file?+
STEP (Standard for the Exchange of Product Data) is an ISO 10303 standard for representing 3D CAD data. STEP files (.step or .stp) preserve full parametric geometry, assembly structure, and metadata, making them the most widely used format for exchanging CAD data between different software packages.
How do I open a STEP file without CAD software?+
CADDaddy lets you open STEP files directly in your browser — no CAD software, plugins, or downloads required. Just drag and drop your .step or .stp file into the viewer and start inspecting immediately.
Can I convert STEP to STL online?+
Yes. CADDaddy converts STEP to STL with one click. Upload your STEP file, preview the geometry, then export as STL for 3D printing or as GLB for web and game engines.
What is the difference between STEP and STL?+
STEP files contain precise mathematical geometry (NURBS surfaces, solids) and assembly information. STL files only contain triangle meshes — an approximation of the shape. STEP is better for engineering and manufacturing; STL is standard for 3D printing.
Is CADDaddy's STEP viewer really free?+
Yes. You can view any STEP file for free with no account. Guest users get one export per day. Create a free account or upgrade to Pro ($19 one-time) for unlimited exports and advanced tools like measurement and sectioning.
What STEP versions does CADDaddy support?+
CADDaddy supports AP203, AP214, and AP242 — the most common STEP application protocols used in mechanical engineering, automotive, and aerospace industries.
Other formats CADDaddy supports
View your STEP file now
No install, no account required. Drop your file and start inspecting.
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