Begin with the decision
A physical model succeeds when it helps a particular audience understand or decide something. State whether the object supports apartment sales, a board review, training, public engagement or an exhibition demonstration. Then rank the three ideas that must remain visible at normal viewing distance. This priority controls where detail is concentrated and where geometry can be simplified. A complete source pack without a communication hierarchy can still produce an expensive but confusing object, so record the intended audience, viewing time, presenter role and final display position before discussing scale.
Issue one controlled source pack
List every supplied file with a revision and date. Native CAD or BIM is useful, but add fixed PDFs showing plans, sections, elevations, colours and the exact geometry authorised for interpretation. Mark confidential or excluded zones and identify which source wins if two files disagree. Photographs help material and context understanding but do not replace dimensions. Include the available footprint, height, access route, lift size, destination floor and plinth capacity, because a beautiful model that cannot reach its room is not a workable deliverable.
Close assumptions in writing
The first proof should show scale, overall dimensions, base treatment, simplification rules, interaction, labels and every unresolved assumption. Review it with design, technical and presentation owners together. Two revision rounds work best when comments are consolidated against a single revision rather than arriving as parallel screenshots. Written proof approval freezes the production basis; later source changes require impact review for cost, programme and already-made parts. Keep the approved proof, final source list, label copy and packing record together so future repairs or updates refer to a known state.