Every Analytics calculation that measures your site starts with a Property component. Use this reference to pick the right property for GBA, GFA, NSA, facade cost, or unit yield, and to know exactly how Giraffe works out each number.

How the property list is built

The Property dropdown in a calculation lists every numeric property found on the geometries in your project. It has no fixed list. A property shows up once at least one geometry carries it.

Each option shows how many matching geometries carry that property, like 3x feats. A property found only on geometries outside your filters shows 0x feats.
Options are sorted alphabetically.
Text properties, like usage names, never appear. Use them in a filter instead.
A property saved in a calculation that no longer exists in the project shows in red with (missing).
Some options show (visible features only). Giraffe only calculates these for geometries that are visible on the map.

Metric and imperial versions

Every measured property in the Property dropdown appears twice: once in metric and once in imperial. For example, grossArea (m²) and grossArea (ft²) hold the same area in different units. Pick the one that matches the unit you set on the calculation.

(m) or (ft) is a length.
(m²) or (ft²) is an area.
An option with no unit, like levels, is a plain number.

Calculated area properties

Giraffe calculates these area properties from each geometry's shape and its settings. Each one appears in the Property dropdown in m² and ft².

Property	What it is	How it is calculated
area	The 2D footprint of a polygon.	The flat area inside the polygon's outline.
grossArea	Gross area of any polygon.	On a building section: area × levels. If levels is blank, Giraffe uses 1. On any other polygon: the same as area.
grossBuildingArea	Gross building area (GBA) of a building section. Only building sections have this property.	area × levels, the same value as grossArea. Use grossBuildingArea to total GBA without counting other geometries.
netArea	Gross floor area (GFA) of a building section.	grossBuildingArea × efficiency. It has no value if the usage has no efficiency set.
saleableArea	Sellable or leasable area (NSA or NRA) of a building section.	grossBuildingArea × sell efficiency. It has no value if the usage has no sell efficiency set.
facadeArea	External wall area of a building section.	For each edge of the footprint: edge length × section height, minus any part of that wall shared with a neighbouring section on the same layer.
partiWallArea	Party wall area shared with a neighbouring section.	The wall area that touches another section on the same layer at the same height.
internalWallArea	Total wall area of a building section.	facadeArea + partiWallArea.
roofArea	Exposed roof area of a building section.	The footprint area, minus any part covered by a section on the same layer that sits directly on top.
dwellingSize	Average dwelling size set on the usage.	Not calculated. Giraffe reads the value from the geometry or its usage.

Wall and roof areas only count neighbours on the same layer. Two touching buildings on different layers each get full facade area on the shared side.

Calculated length and height properties

Giraffe calculates these length properties from each geometry's shape and its stack. Each one appears in the Property dropdown in m and ft.

Property	What it is	How it is calculated
perimeter	The outline length of a polygon.	The total length of the polygon's outer edge.
length	The length of a line, like a road or a fence.	The total length of the line through all its points.
height (visible features only)	The height of the top of the section.	Base height + section height. Section height is levels × floor to floor, or the height you typed in.
baseHeight (visible features only)	The height of the bottom of the section.	Where the section starts in its stack.
depth	The depth of a basement.	The depth you typed in. If it is blank, Giraffe uses the basement's floor to floor.
maxHeight	The maximum height of a generated envelope.	Set by the envelope's height limit.

Input properties

These properties hold values set in the Property Palette or on the usage. Giraffe does not calculate them. Each one appears in the Property dropdown in metric and imperial when a geometry has it.

Property	What it is
floorToFloor	Height of one level.
offset	Distance the shape is offset in plan. Positive is outward and negative is inward.
elevationDatum	Elevation datum for 3D terrain mode. Base height is measured from this value.
slabThickness	Floor slab thickness.
topThickness	Thickness of the top slab. It only changes how the geometry looks.
guidelineOffset	Distance of the dashed guideline drawn around shapes with this usage.
cornerRadius	Rounding applied to corners.
bevel	Bevel size on edges.
bevelSegments	Number of segments in a bevel.
roadWidth	Width of a road, not counting the sidewalk.
pavementWidth	Width of the sidewalk on each side of a road.

Count and ratio properties

These properties are plain numbers with no unit in the Property dropdown.

Property	What it is	Where it comes from
levels	Number of levels in a section.	Set on the geometry or its usage.
efficiency	Share of GBA that counts as GFA, like 0.85.	Set on the usage.
sellEfficiency	Share of GBA that is saleable, like 0.8.	Set on the usage.
parkingBayCount	Number of parking bays in a parking section.	Calculated from the parking layout. It only appears when the project has parking.
stackOrder (visible features only)	Position of a section in its stack. The bottom section is 0.	Calculated from the stack.
layerOpacity, fillOpacity, strokeOpacity	How see-through the geometry is drawn, from 0 to 1.	Calculated from layer and style settings. These are display values and rarely useful in a calculation.

Custom properties

Any numeric custom property you add also appears in the Property dropdown under its own name. Use custom properties for values like dwelling counts, rent per square foot, or cost rates. Add your own numeric properties to geometries or usages to make them available here.

Site area values

Site area values come from the project boundary, not from geometries. Pick them with the Site area component type instead of Property. Each one appears in m² and ft² as "name total area".

Option	What it measures
site	Area of the project boundary.
building	Building footprint inside the site.
landscape	Ground-level landscape inside the site. Rooftop landscape is not included.
rooftopLandscape	Landscape on rooftops.
paved	All paved area inside the site.
road	Roads plus sidewalks.
siteExBuilding	Site area outside building footprints.
siteExAll	Site area not covered by any geometry.
unionAll	Combined area covered by all geometries in the site.

FAR is not a built-in property. Build FAR as a calculation by dividing a grossBuildingArea measure by the site total area.

Property Component Reference