Free Online 3D CAD Viewer

Inspect STL and STEP Files Directly in Your Browser

Open STL and STEP models online without installing specialist CAD software. CAD3D gives engineers, designers, makers, and manufacturers a responsive WebGL workspace for orbiting, panning, and zooming around detailed 3D geometry. Use the measurement tools to inspect dimensions, calculate the model bounding box, review surface area and volume, or create section views along the X, Y, and Z axes to reveal internal features.

Wall thickness analysis highlights thin regions that may affect machining, moulding, additive manufacturing, or structural performance. Your selected model is processed locally in the browser rather than uploaded to a remote conversion service, helping sensitive design data remain on your device. The rendering engine and large file parsers are loaded only when you open a model, keeping the initial page fast while making the full inspection toolkit available on demand.