BIM Documentation Starter

How the method works

1. Sheets per plan is derived exactly: at 1:n, a usable sheet W mm wide spans W x n / 1000 metres, and sheets per plan = max(1, ceil(floor plate / plottable area)) (§3). W and H come from this tool’s standard usable plotting area for the sheet size you choose, which is where §3 carries them.
2. With the optional longest footprint dimension the derivation becomes exact rather than a minimum, tiling the footprint in both directions.
3. Plan sheets = floors that need their own drawings x sheets per plan x the plan types you declare, summed across the disciplines in scope: each selected discipline carries its own plan-types figure, so the sum is the disciplines’ own numbers rather than one figure multiplied by how many of them there are (§3, and §3.1 and §6.1 of v0.1). Those figures live under Advanced, one per selected discipline, each starting at the methodology’s minimum of 1 (§5). A discipline you have not selected has no figure and contributes nothing.
4. Issued set sheets = plan sheets divided by the plans share, rounded up to a whole sheet. That share is the one declared assumption in this tool, and it is named on the result with the register it was counted from (§3, §4).
5. A count you have made yourself replaces the estimate outright and is labelled ENTERED. The estimate stays visible beside it and is never blended with it (§6).
6. Hours = issued set sheets x your hours per sheet. That is where this tool stops: it reports no people, no duration, no capacity and no fee (§3).
7. Anything you have not supplied stays unresolved. It never becomes zero, and the components you have supplied stay visible and separately labelled (§8).

The plans share, and where it comes from

No measured modern benchmark exists. The US National CAD Standard gives a sheet-type taxonomy with no quantity attached, and Scher’s 1972 survey of a school and a hospital is the only measured sheet-type breakdown located. Three public drawing registers were therefore counted sheet by sheet. Each is one project, so these are samples rather than a benchmark, and the finding that matters is the gradient: the plans share falls as the issue advances.

If columns extend beyond the screen, swipe this table sideways or focus it and use the left/right arrow keys.

Declared industry practice, not measured on your projects. Count your own drawing register and replace it.

Three rules hold here without exception: the prefill is visible and editable and the number in the box is the number calculated; a value you have typed is never overwritten, including by a later change of issue; and nothing about building type, asset class or complexity reads into it. Drawing indexes from five or more of your own completed projects would turn this into a figure naming your own practice. Below five records it stays an anecdote.

Limitations, and when this tool refuses

• This is a defensible planning estimate built from your own declared quantities and one cited ratio. It is not a prediction.
• Until hours per sheet is recorded from a completed package, this tool is a sheet counter with an effort calculator attached. The plan count is arithmetically sound; the set count carries one declared assumption; the effort figure is only as good as the rate typed into it.
• A usable plotting area is recorded for A1 only. On any other sheet size the sheet count is withheld rather than approximated from the nominal sheet, because a border and a title block are not a fixed proportion of a sheet.
• The plans share rests on one counted register per stage. Five of your own drawing indexes per stage would turn it into a source naming your practice, with sample size and transferability limits. Below five records it stays an anecdote.
• Linear infrastructure is documented by chainage, not by tiling a footprint, so the plan derivation does not describe it. Refurbishment excludes survey, record-drawing reuse and demolition plans. Under design and build, confirm whose portion of the set this counts.
• Not a fee, not a resource-loaded programme, and not an ISO 19650 conforming information delivery plan. It produces neither a TIDP nor an MIDP.
• The methodology record is version 0.4.0, approved by its owner on 22 September 2026 for preliminary guidance and early-stage estimation, and for nothing beyond that. That is the owner’s own sign-off, not an independent review: no independent professional review of this methodology has taken place, and approval measured nothing. Review by an appropriate professional is still required before this is relied on for detailed planning, a contractual commitment or a final documentation requirement.
• No discipline in scope and no issue declared each refuse outright. A refusal names the missing basis. It is not an error and it never means zero.
• No hours-per-sheet rate leaves the hours unresolved. Both sheet counts are still reported, and this is the most common useful state of this tool.
• No plans share leaves the issued set count unresolved. The plan count is unaffected, because the share reaches only the step from plans to a set.
• A sheet size with no recorded usable plotting area withholds the sheet count and names what is missing. Only A1 carries one, from the methodology’s own declared 631 × 574 mm; the nominal sheet size is never substituted for it.
• A request for a cost, a fee, a headcount, a programme, a sheets-per-1,000 m² rule of thumb or a plans share keyed to building type is refused rather than approximated.

For a cost or a fee, carry the sheet count by hand to cost, fee or rate, headcount or team composition. No value passes automatically between these tools, and the sheet size and scale must match the rate you price it at.

Methodology documentation-sheet-effort-v1, version 0.4.0, status OWNER_APPROVED. Owner Hossam Farag, who approved it on 2026-09-22 for preliminary guidance and early-stage estimation, and for nothing beyond that. That is the owner’s own sign-off and not an independent review: reviewers, none. It is not a validation, a calibration or a certification, and professional review is still required before detailed planning or a contractual commitment. Substantively modified 2026-09-21. The full evidence register, the source classifications and the professional-review trigger table are recorded in the methodology document rather than reproduced here.