Sketch-to-AutoCAD 3D Modelling

I have a set of hand-drawn sketches, photos, and some old scanned plans that all refer to the same small building. What I need is a clean 3D model built in AutoCAD so I can continue refining the design without redrawing everything from scratch.

Here is what matters to me:
• The model must be created in AutoCAD 3D using solid geometry, organised on clear layers, and delivered as a native DWG file (an additional STEP is welcome but not essential).
• Level of detail: moderate. Capture walls, floors, roofs, window and door openings, stair runs, and any built-in cabinetry shown on the sketches. Fine hardware or decorative trim can be left out.
• Dimensional fidelity should match the provided plans within a few millimetres—this is important so that I can generate reliable sections and elevations later.

I will supply the reference material in PDF and JPEG formats, along with key dimensions for anything that might be ambiguous. If areas of the sketches are unclear, I expect you to flag them early so we can resolve questions before the final pass.

Deliverables are accepted once the DWG opens without errors, layers are logically named, and quick spot-checks confirm the geometry matches the reference.