# Defining average radiance material for context

**URL:** <https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170>\
**Category:** honeybee-legacy\
**Tags:** daylight\
**Created:** [February 4, 2019, 7:19am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170 "2019-02-04T07:19:21Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![AryanShahabian](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/aryanshahabian/32/17594_2.png) [@AryanShahabian](https://discourse.ladybug.tools/u/AryanShahabian)\
**Post date:** [February 4, 2019, 7:19am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/1 "2019-02-04T07:19:21Z")

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Dear All,

How do you define a single radiance material to approximately represent multiple materials of an urban context —surrounding the building which is the subject of simulation?  
For instance, imagine that there are some buildings in the surrounding area. All of them have concrete facades with 40% windows (glazing ratio). Is it possible to define and assign just one radiance material to them?

Thank you

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**Author:** ![devang](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/devang/32/21620_2.png) [@devang](https://discourse.ladybug.tools/u/devang)\
**Post date:** [February 4, 2019, 8:07am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/2 "2019-02-04T08:07:46Z")

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[Alstan](http://solemma.net/img/Events/2014/DD2014_Jakubiec_LEEDv4PanelDiscussion.pdf) recommends 30% for the context surfaces on the slide 06.

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**Author:** ![AryanShahabian](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/aryanshahabian/32/17594_2.png) [@AryanShahabian](https://discourse.ladybug.tools/u/AryanShahabian)\
**Post date:** [February 4, 2019, 8:11am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/3 "2019-02-04T08:11:37Z")

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What if when we know that for instance 1/3 of the exterior walls are made of concrete and 2/3 glass windows?

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**Author:** ![devang](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/devang/32/21620_2.png) [@devang](https://discourse.ladybug.tools/u/devang)\
**Post date:** [February 4, 2019, 8:14am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/4 "2019-02-04T08:14:56Z")

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I would recommend using the available information in that case. You should use the out-reflectance value of the glass (generally found in the vendor specification). If you know the opaque surfaces are concrete then you can look for a radiance material for the same on the website I shared.

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**Author:** ![AryanShahabian](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/aryanshahabian/32/17594_2.png) [@AryanShahabian](https://discourse.ladybug.tools/u/AryanShahabian)\
**Post date:** [February 4, 2019, 8:20am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/5 "2019-02-04T08:20:01Z")

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Many thanks for your reply. Would you please share the exact link to the page where I could find the radiance materials? Can’t find them…

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<div class="post-metadata">

**Author:** ![devang](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/devang/32/21620_2.png) [@devang](https://discourse.ladybug.tools/u/devang)\
**Post date:** [February 4, 2019, 8:22am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/6 "2019-02-04T08:22:33Z")

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Please check [Banks of common Radiance materials](https://discourse.ladybug.tools/t/banks-of-common-radiance-materials/5169/2?u=devang)

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<div class="post-metadata">

**Author:** ![devang](https://discourse.ladybug.tools/user_avatar/discourse.ladybug.tools/devang/32/21620_2.png) [@devang](https://discourse.ladybug.tools/u/devang)\
**Post date:** [February 4, 2019, 8:26am UTC](https://discourse.ladybug.tools/t/defining-average-radiance-material-for-context/5170/7 "2019-02-04T08:26:29Z")

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In my experience, I have seen the out-reflectance of glass to be generally 10-12 %