Free Online 3D CAD Viewer

CAD3D is a free online 3D CAD viewer for engineers, designers, makers, and manufacturers who need to inspect STL and STEP files without installing desktop software. Open a model directly in your browser to orbit, pan, zoom, and examine its geometry in a responsive WebGL workspace. The built-in online 3D measurement tool lets you select model points, review dimensions, and switch between millimetres and inches. Use the bounding box view to understand the overall size and volume envelope of a component, or create section views along the X, Y, and Z axes to inspect hidden internal features. Wall thickness analysis highlights thin regions and helps identify areas that may affect machining, moulding, printing, or structural performance. CAD3D also reports useful model properties, including triangle count, bodies, surface area, volume, dimensions, and fill ratio. Files are processed only when you choose one, allowing the page to load quickly while keeping the full inspection engine available on demand for practical CAD review and manufacturing feedback.