Mirror material in Radiance

Hello All,

I was wondering what would the effect of a mirror on daylight so I ran a test.

The gray surface in the image is a mirror and the cyan is a window. The box is 5m wide, 3m high and 10m deep. I made sure that the mirror surface was oriented inwards. I am sceptical about the results I am receiving so I would appreciate an opinion. I am surprised a mirror can contribute this much to daylight levels.

miror test.gh (537.5 KB)


You should start debugging the solution by checking the point-in-time results and compare them by running the simulation for the same time with rtrace (e.g. grid-based recipe).

Hi Devang,

I have been playing quite a lot with reflectors to bring light into what some people call atriums and I call amazingly narrow light wells.

In my experience point in time simulations appear to be quite reliable. However, climate based ones some times show unrealistic results. It was to a point that I decided to discard them. What I use for climate based simulations is customized radiance materials with high reflectances instead of the mirror material, then the results look reliable.

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Have you tried to run the annual study with Honeybee[+]? It uses Radiance native utilities and not daysim.

No, I haven’t. It has been a while since I don’t have projects with reflectors, at that time honeybee[+] was not launched yet. But happy to hear about that change, sounds really good.
Anyway I haven’t tested it yet, as I had a minor problem in the installation, but have been quite busy lately and didn’t have the chance to fix it

Hi @devang

Can you try to setup a view point inside the room to visualize the scene as rendered by Radiance?

It may help you debug if there is any issue with the geometry, material properties, or Radiance ambient parameters.

Something like this?

  1. view towards window:

  2. view towards mirror:

  3. view towards mirror which is changed to wall:

The password for the clusters is 12348765.

miror test _ZJ_v1_mirror.gh (617.4 KB)

miror test _ZJ_v2_noMirror.gh (617.6 KB)

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