CAD Drawing Board

Yes, and in LibreCAD, QCAD, Fusion and anything else that reads DXF. The file uses only the entity types that have existed since the R12 revision — lines, circles, arcs, polylines and text — because those are the ones every reader understands. The version stamp is newer, and only for one reason: the older format stores text in a single-byte code page, and no code page contains the Azerbaijani ə, so a drawing labelled in Azerbaijani or Russian cannot survive it. There is an R12 option for genuinely ancient software.

The board has no fixed unit — it draws in whatever you decide a unit is. The grid and the readouts assume millimetres because that is what building plans are drawn in, so a 2400 wall is typed as 2400. If you are working in metres or inches, treat the numbers as those instead; DXF stores the numbers and lets the receiving program decide what they mean.

Start the line, then type the length and angle in the boxes at the bottom and press Enter. The point lands exactly there regardless of where the mouse is. Ninety degrees is straight up, zero is to the right. For a right-angle-only sketch, turn on "right angles only" — or press O — and every line locks to horizontal or vertical.

Snapping pulls the cursor onto meaningful points of what you have already drawn: the ends of a line, its middle, the centre of a circle, where two lines cross. Without it, two walls that look joined are a fraction of a millimetre apart, the area comes out wrong, and the DXF has a gap that the next program will complain about — none of which is visible at any zoom you would normally work at.

No. The drawing is held in the page, the export files are built in the browser and handed straight to the download, and nothing is sent anywhere. Closing the tab loses the drawing, so use Save to keep it — that writes a file to your device which Open reads back.

Far larger than anything you would draw. The working area is bounded by what the numbers themselves can hold precisely, which at millimetre precision is a span wider than the solar system. In practice the limit you will meet is how many shapes stay comfortable to redraw, which is in the thousands.