BuildingDefinition Syntax

The Generate Building Information component (GenBuilding) accepts a single text string and generates a complete BuildingData object.

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Full Syntax

<Template>, <Floors>, <Spans> [, Key=Value ...] [, cut:<anchor> <W>x<H>[@<N>F|@<N>F+] ...]

All three primary tokens are comma-separated. Additional Key=Value options and cut: clauses (v5.7.0) can follow, in any order.

The comma is the token separator

The whole definition string is split at commas first. No token — including option values — may contain a comma.

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Token 1 — Template

The building use type. Determines default story height, span, structural system, sections, and load conditions.

Office
Mansion
Factory
Hospital
School
SRC
W

See Building Templates for the full definition of each template.

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Token 2 — Floors

Basic: floor count only

5F

Generates 5 identical stories using the template's default story height.

Custom: specify story heights (mm)

5F:4000

All 5 floors at 4000 mm.

5F:5000:4000:4000:4000:3000

Per-floor heights: 1F→2F = 5000, 2F→3F = 4000, 3F→4F = 4000, 4F→5F = 4000, 5F→RF = 3000.

Height count rules

• If fewer heights than floors are provided, the last specified value repeats for remaining floors.
• If more heights than floors are provided, excess values are ignored.

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Token 3 — Spans

Basic: bay count only

4x3

4 bays in X, 3 bays in Y. Uses template default spans.

Uniform span: all bays the same size

4@8000 x 3@6000

4 X-bays each 8000 mm, 3 Y-bays each 6000 mm.

Different span sizes per bay

Per-bay span lists (e.g. 3@7200,8000,6000) cannot be written here, because the comma is the top-level token separator. Generate with a uniform span, then adjust individual spans in the Grids Editor (D06).

Separators

X and Y are separated by any of: x · X · ×

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Options (Token 4+)

Additional comma-separated Key=Value pairs. Order is not significant.

Structure

Override the structural catalog while keeping the base template's geometry (story height, spans, offsets).

Structure=SRC
Structure=RC
Structure=W
Structure=S

Example: An office building with SRC structural sections:

Office, 5F, 4x3, Structure=SRC

TopOfBeam

Override the beam top elevation offset from floor datum (mm).

TopOfBeam=-200

SlabOffset

Override the slab top elevation offset from floor datum (mm).

SlabOffset=50

Unit

Override the unit system.

Unit=metric
Unit=imperial

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cut: — Void Cut-outs (v5.7.0)

Append any number of cut: clauses to void bays at generation time (L-shapes, setbacks, notched plans). The generator always builds the full rectangle first; a post-process then sets Is_Void=true on the affected records. Nothing is deleted, so voided bays can be restored later (e.g. in the Layout Editor).

cut:<anchor> <W>x<H>[@<N>F | @<N>F+]

Element	Meaning
<anchor>	N / S / E / W / NE / NW / SE / SW. N = +Y side, E = +X side. A corner anchor (NE etc.) voids the W×H bays starting from that corner. An edge anchor (N etc.) attaches to that edge and centers the block along it (an odd remainder is biased toward the W / S side)
<W>x<H>	Bays in X × bays in Y (separators x · X · ×)
@<N>F	Void on floor N only
@<N>F+	Void on floor N and all floors above
(omitted)	Void on all floors

Office, 5F, 4x3, cut:NE 1x1              → L-shape (NE corner bay voided on all floors)
Office, 5F, 4x3, cut:N 4x1@3F+           → Setback (entire north row voided from 3F up)
Office, 5F, 4x3, cut:NE 1x1, cut:SW 1x1  → Multiple clauses allowed (applied independently)

Rules

• Case-insensitive (cut:ne 1x1 works).
• Multiple cut: clauses are applied independently; the voided cells are their union.
• What gets voided (consistency set, per floor): floor areas (slabs / secondary beams, with tertiary beams following their parent) covering the target bays → girders whose flanking in-grid bays are all voided (a girder with at least one live bay is kept — the edge of the cut) → columns whose touching in-grid bays are all voided.
• Out-of-range clauses never abort generation. A clause larger than the grid (W > X-bays or H > Y-bays) or a floor outside 1..<floor count> is skipped, reported as a Grasshopper Remark bubble.
• A malformed clause (wrong grammar) is skipped with a Warning.
• The Info output reports a Cuts line: number of clauses and number of records set to Is_Void=true.

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Complete Examples

Prompt	Description
Office, 5F, 4x3	5-floor S-frame office, 4×3 grid, all defaults
Mansion, 10F:3000, 3@6000 x 2@8000	10-floor RC mansion, 3000 mm stories, custom spans
Factory, 2F:8000:6000, 5@10000 x 3@12000	2-floor factory with large bays
Hospital, 8F, 6@8000 x 4@8000	8-floor RC hospital
Office, 5F, 4x3, Structure=SRC	Steel office geometry + SRC catalog
W, 3F:3000, 5@3640 x 3@3640	3-floor timber building, 910mm modular grid
Office, 5F, 4x3, cut:NE 1x1	L-shaped plan (NE corner bay voided, v5.7.0)
Office, 5F, 4x3, cut:N 4x1@3F+	Setback from 3F up (v5.7.0)
Office, 5F, 4@8000 x 3@7200, TopOfBeam=-200, SlabOffset=50	Full options

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Warning Handling

The parser is fault-tolerant. If a token cannot be parsed, a warning is issued and a default value is used. Warnings appear:

• In the Info output of the component.
• As Grasshopper runtime warning bubbles on the component.

Condition	Fallback
Template not recognized	Office
Floor count missing	3F
Span token missing	3x3
Invalid story height value	Template default height
Invalid span value	Template default span
Unknown Structure= value	Default catalog from template
Malformed cut: clause	Warning; that clause is ignored
cut: clause larger than the grid, or floor out of range	Remark; that clause is ignored (generation continues)

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更新履歴

バージョン	変更内容
v5.9.0	構文の変更なし（Grid_Nodes（交点移動）の生成は Grids Editor (D06) / AI Building Generator (I06) 側で対応）
v5.7.0	cut: 節（欠き取り指定）を追加

※ 2026-07-14: 実装と照合し、現行パーサでは機能しない記載（ベイごとの混在スパン 3@7200,8000,6000 / Origin=x,y — いずれもカンマがトークン区切りと衝突）を削除しました。