Finding area of contours in Ecotect/Radiance analysis grid

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February 9th, 2010

Finding area of the contours of the ecotect analysis grid was something which I had to do for my dissertation relating to lighting analysis in atriums and the adjacent spaces. One of the grids whose area I had to find for the different bands of daylight factors is:

One of the easiest methods is clicking on the following:

REPORT > REPORT GENERATOR > Analysis Grid > Percentage Contours

which presents the following screen:

At the first glance, the table here gives the information we require, very nicely formatted as well. On a closer look, what it is doing is just adding the number of grid points which fall between a particular range (daylight factors from 0 to 10 in this case) and give the percentage from the total number of grid points. According to this report, no part of the floor get daylight factors in the range of 9-10.

The method I prefer is using Illustrator and a free plugin called path area. You can find it from the Telgraphics website. Please install it before continuing.

This did not work for me in Illustrator CS4, so the following steps are for Illustrator CS2:

1. First, clean up the grid for export. Switch off all zones (Zone Management tab), untick everything in the Data Overlay section (Display Settings tab) and select No Context in the Model Context section (Display Settings tab). Under Grid Settings section (Analysis Grid tab) make sure there is tick mark ONLY against Show Gridlines, Shade Grid Squares, Show Contour Lines. This should lead to a grid looking like the following:

2. Click on the little camera button on the bottom right part of the window, and select Copy as Metafile.

3. Open up Illustrator (CS2 here). Create a new document and press Ctrl+V to paste the copied meta file.

4. Ungroup the image by right-clicking on it and selecting Ungroup.

5. Select 1 square from the colour band whose area you want to know. Click on Select > Same > Fill Color. I have made a keyboard shortcut for this command as Shift+Ctrl+1.

6. Once all the same colour shapes are selected, click on Filter > Telegraphics > Path area. I have created a keyboard shortcut for this as Shift+Ctrl+2.

7. This shows a dialogue box which gives the perimeter and the area.

8. Now that you have the area, you can easily calculate the percentage of area lying in that range!

I know it’s not the true area, but you can use a multiplier to find the exact area as for your building using a simple excel formula.

Tags: analysis grid, cs2, export, Illustrator, path area, radiance, telegraphics
This entry was posted on Tuesday, February 9th, 2010 at 11:20 PM.
Category: Ecotect, Illustrator, Tools.

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