Draft opens CAD files right in your browser. DXF drawings get the full treatment — pan, zoom, layer toggles, distance / area / angle measuring with point snapping, plus light editing: move, delete, draw lines, circles and text, then export a valid DXF again (or a PNG/SVG snapshot). 3D models — STL, 3MF, OBJ, PLY and real STEP / IGES CAD — open as a solid shaded model you can spin, with shaded, edges and wireframe views. DWG is a closed format — save it as DXF, STEP, STL or 3MF in your CAD app first. Nothing is uploaded.
Draft reads ASCII DXF (the export every CAD app offers) and renders lines, polylines, circles, arcs, ellipses, splines (approximated), text, block inserts, hatch boundaries and dimension geometry; paper-space layouts may draw simplified. Snapping locks the cursor to endpoints, midpoints and centres while measuring or drawing. Edits are conservative: everything Draft can't display is preserved untouched in the exported DXF. 3D models — STL and OBJ (binary/ASCII), PLY, 3MF, and STEP/IGES — are tessellated to a shaded mesh; the STEP/IGES engine is a one-time ~8 MB download the first time you open one. Everything runs on your device.