Photopic lux for view point


I am trying to make a script in grasshopper to calculate the photopic lux for a particular view point in the room. I am considering only artificial lighting for this research.

Purpose of research- To calculate various photopic lux as I change the distance between the lighting fixtures and the view point.

I have made the script and connected all grids to the analysis part but I am facing problem of calculating my results. I have attached screenshot of some part of the script and also my ‘.gh’ file along with the discussion.

Thanks for any help!

box (535 KB)

Hi Anmol,

I think the geometry in your gh file is not internalized. Can you share the rhino file, and your IES file, as well?



Thanks for the reply! Below I have attached my rhino file and the IES file.

Thanks once again!

trial- square box- 24 sept.3dm (56.8 KB)
66813.IES (9.21 KB)

Hi Amol,

A few things:

  1. You should update your HB installation by using the Honeybee_update_honeybee component as the latest release contains some bug-fixes that Chris Mackey and I had made over the past month.

  2. You need to specify a sky definition to make the simulation work. In your case it will be dark sky as you are only simulating electric light.

  3. I am not sure you can visualize a single point with a mesh. (Maybe you can… Chris , Abraham, Mostapha or Anton can better answer that question).

  4. Your simulation will be in meters. So, I think you should either resize your room (if your original dimensions are in feet) or increase the number of fixtures to get a decent illuminance level.

  5. Honeybee calculates photopic illuminance by default.

  6. I made your simulation work by pasting the contents of your ies file directly into a text panel and linking it to the _iesFilePath. You can also make it work by simply specifying the path directly (ie. something like c:\light.ies etc…).

See the attached file. (527 KB)

1 Like

Hi Amol and Sarith,

You can analyze a single point but not visualize with a mesh (there is no mesh).

I would try to attach a geometry to the point (sphere, for example), and color it according to the result.


Thanks for that idea! I usually end up just tagging text when there is a single point since I could not think of any other way to visualize it.


Hello Abraham,

Thanks for the suggestion! I would try it by attaching the geometry and then colouring it.


Hello Abraham,

Can you please elaborate the idea of analyzing a single point?