Why is there a 2 phase calc in the 3 phase recipe?



I was following the workflow of the 3 phase calculation process. When reading the batch file (and then making a calculation) I realised that honeybee makes a 2 phase DDS calculation excluding all window groups, then does the 3 phase calc I’m interested in. I don’t understand the benefit of making a 2 phase calculation first as it adds time to an already long calculation time.

For example, I want to test window arrangements for a new room. So I make each possible window as a group. I have no windows as a ‘window surface’ (only window groups). Then I have to wait whilst honeybee makes the default calculation (a 2 phase calculation) of a room with no windows. A person could argue that for the default calc there will be a particular window that will never change hence it can be included in the default calc, but for most my projects I want a black canvas to start with.

What am I missing here? What is the benefit of making this 2 phase calculation when I want to make a 3 phase calculation?

Thanks for input


this is the part of the batch file I’m referring to

[1/3] scene daylight matrix
echo :: :: rfluxmtx - [sky] [points] [wgroup] [blacked wgroups] [scene] ^> [dc.mtx]


Hi @john.everist, See here: Three phase vs five phase component resulting batch file calculations

Also documented on this Wiki page:


Thanks. For me, it would be useful to be able have an option to bypass the 5 phase part if there is no value in it for the calculation i am running.


Agreed but to do that we need to know that there is no source of light to outside except for the window groups which is very hard to guess. I agreed we should expose it as an input that user can overwrite. When finally that next release comes out this should be addressed! :crossed_fingers: :pray: