<b>The backstory</b> Back in the mists of time (circa 2005) we achieved a planning permission for a large masterplan project in a European capital (lets call it Donlon). Part of the Urban Design guidelines was a design parameter for the public realm that public spaces between buildings would be guaranteed visible sky for a given percentage of the street or square as a proportion of the linear length. This parameter was for 40degree 2D splay oriented at a normal to the world in the centre of the space at a given point with its vertex at ground level. To ensure the possibility of a variable skyline (no enforced rigid setbacks) the splay was allowed to wobble - again this parameter varies by space dependant on character and North-South / East-West orientation.
<b>The problem</b> Sounds good, but how do you manage this with a massive scheme where some buildings are already designed, some are emerging and some wont be looked at for years. Either you have have some poor bugger drawing infinite sections and running options everytime something changes or you automate the calculation somehow. <b>Step forward Grasshopper</b> Admittedly this could have been a purely scripted solution, but given that i have learned grasshopper prior to learning how to use Rhino its be learn as you go. Besides Grasshopper is a joy to use. The file <img src="http://grasshopper3d.googlegroups.com/web/ UrbanDaylightAnalysis.png" /> is the result. all in its the most complicated ratio calculation I have had to construct in a while but it made a change from vba for excel <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays1.gif" /> <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays2.gif" /> <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays3.gif" /> <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays4.gif" /> <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays5.gif" /> <img src="http://grasshopper3d.googlegroups.com/web/ parametric_daylight_splays6.gif" />
