Drawings or model as the deliverable

What the contractual deliverable is

The construction documentation has a content set by legislation, and that is generally drawn and written documentation. The content of the detailed design.

The model, by comparison, is often the designer’s working tool — the drawings are produced from it, but it is not necessarily part of the deliverable.

Why it is still worth settling

For later alteration

With a model in hand, designing an extension or an alteration is much cheaper.

For operation

The data in the model — materials installed, systems — is useful to operations too.

For manufacture

If the client later has it made elsewhere, the transferability of the model matters. What the system exports.

For archiving

A model archived in an open format is still readable years later.

What to record in the agreement

1. What the client receives: drawings, model, both.
2. In what format: native, open format, PDF.
3. At what level of development. Levels of development.
4. What it may be used for and with what liability.
5. Who may maintain the model in future.

The liability question

The designer is liable for their drawings. If the client receives the model and somebody else edits it on, the liability position changes.

So it is customary to hand the model over for information and to fix the contractual deliverable in the drawn documentation. That is not withholding but keeping the liability clean.

The practical recommendation

The handover package should contain:

• the contractual drawn documentation,
• the model in an open, archivable format,
• the data on the materials installed,
• and the documentation of the concealed work.

Handover documentation.

The point

The drawing is the contract, the model is the value. Get both — and settle in advance what each may be used for.