Can I Calculate the Building Compactness Ratio?

The following script will do this for you, allowing you to calculate the ratio of zone volume to floor area. It also demonstrates the generation of a simple HTML report showing values for each thermal zone in the model, as well as summed overall values at the bottom.

-- ------------------------------------------------
-- BUILDING COMPACTNESS CALCULATION:
-- This is a simple script that cycles through all 
-- thermal zones in the current model and builds up 
-- a table of the ratio between volume and floor 
-- area to give a simple compactness ratio.
-- ------------------------------------------------

-- Get number of zones in the model.
zones = get("model.zones")

-- Initialise some variables.
sum_v = 0
sum_f = 0

-- Initialise the heading of a report table.
-- Using the '|' character as a column separator.
reportData = "ZONE NAME|VOLUME (V)|FLOOR AREA (A)|V/A(BCR)\n"

-- Cycle through model zones.
for z = 1, zones-1, 1 do

  -- Check for a thermal zone.
  if (get("zone.thermal", z)) then

    -- Get volume and floor area of zone.
    v = get("zone.volume", z)
    f = get("zone.floorarea", z)

    -- If both are greater than zero,
    if (v > 0.0) and (f > 0.0) then	

      -- output zone data as another table line.
      line = format("%s|%0.2f|%0.2f|%0.3f\n", 
        get("zone.name", z), v, f, f/v
        )

      -- Concatenate line to reportData text.
      reportData = reportData .. line

      -- Sum up volume and areas.
      sum_v = sum_v + v
      sum_f = sum_f + f

    end

  end

end

-- Add the totals line to the table.
line = format("OVERALL|%0.2f|%0.2f|%0.3f\n", 
  sum_v, sum_f, sum_f/sum_v
  )

reportData = reportData .. line

-- Create a HTML report - other report types 
-- include: 'text', 'box', 'html' and 'excel'.
reportOpen("html", "")

-- Adds a <H1> title line to the HTML page.
reportAddLine("Compactness Ratio Report", "h1");

-- Adds a normal <p> line to the HTML page.
reportAddLine("The BCR is given as the ratio of"
  .. " total volume over floor area for each"
  .. " thermal zone within the building model."
  )

-- Generates a table within the HTML page 
-- using 'reportData' which contains 4 columns, 
-- 1 header row and 1 footer row.
reportAddTable("Building Compactness Ratio (BCR)", 
  reportData, 4, 1, 1
  )

-- Close and display report.
reportClose()

You could easily modify this script to show floor area vs exposed surface area or basically any other set of building criteria.