Ask-Built: a drawing is an answer, not a deliverable

Ask-Built is a theory by George Billam (first set out 30/10/2026): if the information model is complete and trusted, the drawing stops being a deliverable and becomes an answer. Nobody produces a drawing until someone on the job asks a question that needs one. Then it is generated for that person, that package and that moment, and thrown away when the question changes.

The name is a play on "as-built". As-built records what was built after the fact. Ask-Built says the documentation of a building should be produced by asking, not by issuing.

The one-line version: a drawing is an answer to a question someone hasn't asked yet, so stop answering in advance.

The theory

Today we push drawings: a design team decides in advance which plans, sections, elevations and details every trade might need, draws them all, revises them all, and issues them in packages. Most of that effort answers questions nobody asks, and every change has to be chased through every sheet that shows it. Ask-Built flips this from push to pull.

Where a building information model holds the design to the level the job needs, the model is the deliverable and every drawing is a query on it. Drawings are generated on demand, scoped to the person asking, and carry the model revision they were drawn from.

Where it came from: the question started in conversation about AI agents driving Revit through MCP. If an agent can already open a model and produce sheets on instruction, the next step is obvious: why instruct it at all? A subcontractor says "my package is the data containment, show me what I need to install it" and gets exactly that, drawn from the live model.

Five principles: the model is the only source of truth (drawings are views, never records); no question, no drawing (nothing is drawn speculatively); scoped to the asker (the containment installer sees containment and nothing else); disposable and stamped (every generated drawing carries its model revision and expires when the model moves on); the asking is the audit trail (who asked what, when, and what they were shown is itself a record, closer to the Building Safety Act's golden thread than a register of issued PDFs).

How it works on a job

Take a fit-out where the data containment installer starts on Monday. Today they get the full electrical set and find their scope. Under Ask-Built they ask for their package and get one drawing: containment routes, setting-out, fixings and the interfaces with ceilings and other services, nothing else. A model change retires the drawing instead of triggering a reissue.

What already exists

The "no drawings" half of this is not new: Scandinavia has built bridges, hydropower stations and city-scale schemes with the model as the contract document, including a 634-metre bridge built with no drawings at all (Randselva Bridge, Norway) and the Slussen redevelopment in Stockholm. What those projects did not solve is the person on site who cannot or will not navigate a model. Ask-Built's contribution is the second half: keep the drawing, but make it a generated answer to a trade's question rather than a pre-issued sheet.

Total BIM (Chalmers University) makes the model the legally binding construction document but asks site workers to use model-viewer software, keeping a structural engineer on site to pull measurements. Ask-Built moves that job to the system. Drawingless / Zero Drawings (Sweco) removes the drawing entirely; Ask-Built keeps it as the trade's preferred interface and removes only the pre-production of it. Level of Information Need (BS EN ISO 7817-1) is the closest cousin in UK standards: it defines what information each party needs; Ask-Built is the delivery mechanism.

Objections

"Subbies aren't technical enough to query a model." Ask-Built asks less of them than today. They currently find their scope across a full drawing set and a spec. Under Ask-Built they tick what their package includes, or say it in plain words, and get one drawing.

"Drawings are the contract documents." True for nearly every UK project today. Ask-Built needs the model, plus the rules for generating views, to be the contract document. Until then it runs as a production method sitting behind conventional issued sets.

"AI will hallucinate a dimension." Ask-Built does not let AI invent geometry. The AI chooses which elements, views and annotations answer the question; dimensions and positions come from the model.

"Who carries liability for a drawing nobody drew?" The designer is liable for the model and for the view rules; the system records exactly what was shown to whom. That is a cleaner position than today, where a superseded sheet on site is a common cause of error.

"Models are never complete enough." Correct, and the theory says so. Ask-Built raises the stakes on model quality. Where the model is thin, the system should refuse the question and flag the gap, not guess.

Using it in talks

The 60-second version: "We spend a huge share of fee producing drawings in case someone needs them. I call the alternative Ask-Built. If the model is good enough, a drawing is just an answer to a question. So don't answer in advance. Let the containment installer say 'show me my package' and generate exactly that, from the live model, stamped with the revision. The Scandinavians have already proved you can build a 634-metre bridge with no drawings at all. What they hadn't cracked is the operative who doesn't want to drive a 3D viewer. AI cracks that. The drawing survives; it just stops being something we produce and starts being something the job asks for."

Soundbites: "A drawing is an answer, not a deliverable." "As-built tells you what happened. Ask-Built tells you what you need." "We don't print a website for every visitor. Why do we print a building for every trade?" "Stop answering questions nobody has asked." "The skill barrier should sit with the system, not the operative."

Companion theory: Ask-Built covers the way out of the model. The way in, one open building source with every application as an interface on it, is set out in Interfaces and Singularity.