Honeybee simulations for "curved NURBS surfaces"

Hi Mostapha, Chris and all,

In the new release of Honeybee (http://www.grasshopper3d.com/group/ladybug/forum/topics/new-release…), it is said that “energy results can be obtained for curved NURBS surfaces as well as unconventional window configurations”.

And I also noticed the following information form the optional input in the runEnergySimulation component.

“meshSettings_: Optional mesh settings for your geometry from any one of the native Grasshopper mesh setting components. These will be used to change the meshing of curved surfaces before they are run through EnergyPlus (note that meshing of curved surfaces is done since Energyplus is not able to calculate heat flow through non-planar surfaces). Default Grasshopper meshing is used if nothing is input here but you may want to decrease your calculation time by changing it to Coarse or increase your curvature definition (and calculation time) by making it finer”.

1) My case is an one-story, rectangular-plan large hall (40m70m25m) with a curved roof. The roof surface is a part of a standard sphere and the walls and floor are all planar (the each wall has one curved edge as showed in the image).

For testing, I threw the original curved roof surface into daylight and energy simulations without making customized meshings, because I assumed that it might be automatically converted to meshs by Honeybee - **Am I right? As showed in the image, how can I reduce the number of meshs in a proper way? Must two connected surfaces (i.e. wall and roof) be STRICTLY/SEAMLESSLY connected or not **(considering different divisions of meshs in the respective surface)? - Is a connection tolerance allowed?

2) But, when I run the annual daylight simulation for this case, it gave me a lot of warnings “oconv: warning - zero area for polygon”.- is that normal? and how to avoid this? Does the daylight simulation allo****w “****curved NURBS surfaces”?

  1. Moreover, when I run an energy simulation for this case, it costed extremely long time. It was just so long that I did not even have results out of one simulation. - I guessed it might be the problem caused by the curved roof surface (or automatic meshing?), but I don’t have experience of converting a curved NURBS/spheral surface into correct meshs that can be recognized by Honeybee simulations (Daylight and Energy) in a proper way.

  1. The large window on the wall was generated by the “_glzRatio”. But the automatically generated wall meshs around this window are just too “fine”, which might largely increase simulation time. Is there a proper way to get rid of it? (Considering that the size, shape and position of the window will have large influence on the daylight distribution in the building, it is worthy to keep the size, shape and position of the window as it should be in reality).

In sum, considering all above, could your please provide me some suggestions/tutorials/links that might be helpful for dealing with “curved NURBS surfaces” in Honeybee simulations.

Thank you all in advance!



20150511_1_test.gh (598 KB)

Hi Ding,

I am also working on a nurbs curved facade. Did you manage to find what the problem is?