Open a .step or .stp file in your browser and look at the part: rotate and zoom it, read its dimensions, slice a cross-section through it, and measure between any two points. No CAD package, no install and no signup.
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How viewing a STEP file works
A STEP file stores geometry as mathematical surfaces, which is why CAD packages can edit it and why a browser cannot draw it. To show you the part, the file is uploaded and FreeCAD's OpenCASCADE kernel tessellates those surfaces into triangles, and that mesh is what appears above. It is the same step a slicer performs before printing.
That is a real difference from our STL viewer, which never uploads anything because a browser can read STL directly. If the part is confidential, that distinction is the one to weigh. Files here are deleted within 24 hours.
What you can do with the model
Drag to rotate, scroll to zoom, right-drag to pan. The panel gives you standard Iso, Top, Front and Right views, model and background colours, and a switch between millimetres, centimetres and inches. Cross-section cuts the part along any axis so you can check a wall thickness or find an internal cavity, and point to point measurement gives the distance between any two places you click. The readouts cover bounding box, triangle count, surface area and enclosed volume.
If you want to keep the mesh rather than just look at it, the STEP to STL converter returns the same tessellation as a file. For background on the format itself, see what is a STEP file.
Frequently Asked Questions
Yes, that is what this page is for. Drop a .step or .stp file and the model appears, with no CAD package and no signup. Most desktop STEP viewers want an install and often an account.
Yes, and this is worth being straight about. A browser cannot read STEP: the format describes CAD surfaces mathematically rather than as triangles, so something has to tessellate it into a mesh first, and that happens on our server. Our STL viewer is genuinely local because a browser can read STL directly. This one cannot be. Files are deleted within 24 hours.
Yes. STP and STEP are the same format with two conventional extensions, and both are accepted end to end.
Bounding box dimensions, triangle count, surface area and enclosed volume, plus a mesh check for open boundary and non-manifold edges. You can rotate and zoom, cut a cross-section along any axis to see inside the part, measure between two points, and change the model and background colours.
Because you are looking at a mesh, not the original surfaces. Tessellation approximates curves with flat triangles, so a cylinder becomes a many-sided prism. The underlying STEP is still exact; the display is an approximation of it, as it is in any slicer.
The STEP to STL converter produces the same mesh as a file you can keep. This page is for looking rather than for downloading.
No. Nothing is written back to your file. The tessellation produces a separate mesh for display and the original is untouched.
Large assemblies take longer to tessellate, since the work happens on a server and scales with the number of surfaces. A single part is quick; a full assembly with hundreds of components is not.