CAD and Drawings

Missing CAD Models, Drawings, Dimensions, and Package Data

How engineers should handle missing mechanical files, bolt-hole dimensions, land patterns, package drawings, and incomplete supplier geometry.

Back to Engineering FAQs

Is a 3D CAD model enough without a drawing?

Sometimes, but not always. For many manufactured parts, the model may define geometry while the drawing defines critical dimensions, tolerances, notes, finishes, inspection requirements, and revision control. If a supplier expects the model to be controlling, that should be explicit.

What should be requested when dimensions are missing?

Ask for the current 2D drawing, STEP or native CAD file, package outline, land pattern, hole pattern, critical tolerances, revision, and any standards used for model-based definition. For electronics, request the package drawing and recommended footprint.

How should missing geometry be shown in a comparison?

Mark it as missing or supplier-confirmation required. Do not infer bolt-hole patterns, package dimensions, or mounting geometry from images unless the source is clearly dimensioned.