Drop a STEP file, check the preview, download GLB. The conversion runs in your browser, so your model never leaves your device.
Files are processed entirely in your browser. Nothing is uploaded to a server.
Any 3D edit is just a prompt away.
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STEP (.step / .stp) is a CAD exchange format that describes exact surfaces such as cylinders, fillets, and splines instead of triangles. FreeCAD, Fusion, and SolidWorks all export it.
The converter writes GLB, so the result loads directly in web viewers, e-commerce embeds, and most game engines.
The conversion runs Open CASCADE, the same geometry kernel FreeCAD uses, compiled to WebAssembly. Your CAD surfaces are tessellated into a watertight mesh right in the browser tab.
GrandpaCAD turns a text prompt into a ready-to-print 3D model. Functional parts, organic shapes, multi-color prints. No CAD skills needed.
"Phone stand with cable slot, 70mm wide, 15 degree angle"
