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Areas Properties Panel - Project level

In the Properties Panel for the Rooms Module, there are 5 Areas related headings with groupings to record or display: 

1. Gross/Net factor for the Functional Level section provides an editable field to enter a Grossing factor (expressed as a ratio) to Planned or Programmed Functional Levels. For example to apply a Gross/Net factor of 20% to a Functional Level you enter "1.20" and this will show also as 20% in the adjoining field.

This Gross/Net Factor in the Properties panel is then used to calculate the following

  • Planned Net area (calculated from a given Planned Gross Area)

  • Programmed (Briefed) Gross area (calculated from the Function Level Net Programmed Area)

  • Delta values for Designed Gross (differences between Designed and Programmed Areas)

2. Planned Areas  (Gross and Net) section allows you to enter a Net and/or Gross Planned area for the selected Functional Level which in turn then calculates the other (Gross or Net) value according to the Gross/Net factor. Refer Warning panel below. For Planning Gross/Net Calculations the Gross/Net Factor should only be applied at one Functional Level, preferably the lowest Level if you need the same Grossing to appear for each Functional Level above.

3. Programmed (Briefed) Room Count and Net and Gross Areas Areas section provides a summary of

  • Room Count for the selected Functional Level as well as a

  • Net Area and a

  • calculated Gross Area which represents the total of Grossed Areas below that Functional Level - with the additional Gross/Net factor for the current Functional Area applied as well.

This enables differing Grossing Factors to be applied to Functional Levels as per the Project Design Programme (Brief) allowances for Circulation / Travel / Plant / Planning Contingencies / Wall thicknesses etc.

4. Designed Areas Gross and Net Areas section which provides an editable field to enter a Gross Designed Area which is sourced by either

  • syncing to "Areas" representing Departments or Floor Levels in the Building Model or by

  • manual entry in dRofus.

The Net area total is the sum of all Designed Rooms contained within the selected Functional Level.

5.Diff (Designed - Programmed) section provides calculations of the difference between Designed and Programmed measurements in the Function Level

  • Diff Net displays the Net difference between Designed and Programmed in unit measurements used on the project

  • Diff Gross displays the Gross difference between Designed and Programmed in unit measurements used on the project


  • areas for non-functional spaces (such as corridors and plant rooms) will also be included as part of the Net Area for Designed Areas.

  • The Gross/Net factor for the Functional Level is not applied to the total of the designed areas. It only applies to Planned or Programmed Areas.

Changing the Planned "Gross" value will recalculate the "Gross/Net factor" to match the Net value.

Changing the Planned "Net" value will recalculate the "Gross" value according to the value given in the "Gross/Net factor"

As the same Gross/Net factor is also used for the Programmed Area calculations if you change the Planned "Gross" value then the "Gross/Net factor" will change and so will the Programmed Gross Area calculations.

This should be avoided as ideally the Planned Areas section is only used for schematic early planning and is then superseded by the use of the Programmed Areas and Designed Areas at a later stage and so changes to Planned Areas should not overlap with Programmed Areas.

If there is no requirement for Gross/Net factors in your Project, enter "1.000" as the default Gross/Net factor, and as Project Gross/Net factor.

The use of Cumulative Gross areas for Programmed Areas in the dRofus project

A Gross/Net factor can be applied at any Function level in the Function structure as either a percentage or as a multiplying factor (eg. 25% or 1.25).

The example shown below compares a conventional Schedule of Accommodation (SoA) to the same data and settings in dRofus.

In the SoA the there are separate Gross/Net factors applied at at the

  • Zone level ("Zone Gross/Net factor") for Engineering Allowance, and at the

  • Sub-department Levels ("Sub Department Gross/Net factor") for Circulation.

The calculated Programmed Gross Areas in the Green, Yellow, Purple and Blue sections are added together and the Zone Gross/Net factor is then applied to the combined Gross in the Red sections.

In summary - the calculations around the Gross/Net (also known as Grossing) factor depend on the assumed work process. 

  • For Planned Areas the Gross/Net factor calculates the required Planned Net Area from a given Planned Gross Area at any given level of the Function Tree or, alternatively if a Planned Net and a Planned Gross are entered then the Gross /Net Factor is calculated (refer warning above). 

  • For Programmed Areas, the Gross/Net factor is applied to the sum of the calculated Programmed Gross Areas of the Functions below which in turn have been calculated from the sum of the Programmed Room Areas with any Functional Area Grossing applied at the lower level.

  • For Designed Areas, the Designed Gross/Net factor is calculated as the ratio between the Designed Area Gross (as entered manually or synced from a Departmental Area item in the model) and the sum of the designed areas of all Rooms in those Departments. 

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