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What is the (Current) State of the OpenStudio Radiance Measure?

asked 2018-06-25 14:34:11 -0500

updated 2018-06-26 03:43:13 -0500

Searching for documentation

  • I went through the official user documentation which is really short, only these two documents: Radiance Tutorial and Radiance Reference Guide.

  • I pretty much went through all the Youtube videos I could find on NREL’s channel about Radiance (a list is here)

  • I also looked at quite a few questions about daylight and openstudio on UnmetHours.

Yet I still have many questions and/or concerns about the Radiance Measure.

I know this isn't the original intent of UnmetHours, but I feel like a global post (like community wiki) would be helpful, so pardon me for asking multiple things in this thread.

What is the current state of the OpenStudio Radiance Measure and what can we expect going forwawrd?

  • I read in this question that there is zero truth reporting at the end of the perimeter zone since the boundary is opaque. How should we place the illuminance map regarding the exterior walls?
  • Can you place a non-rectangular illuminance map? In Sketchup Plugin it seems you can't. If not, how do you deal with non rectangular spaces?
  • Is there any measure that would add an illuminance map to all spaces or do you have to do it manually? (Seems like this would be very doable to create one using the SDK...)
  • Will Dview eventually support visualizing the illuminance map results, or are we stuck installing Results Viewer from OpenStudio 2.2.0 for that?
  • Radiance Measure calculates sDA, but does the Radiance Measure calculate the ASE metric? (required by LEED).
  • Given the fact that Sketchup Make is apparently turning into a web application with no plugins at the moment (and no communication from Trimble about when/if plugins will be available), is there any other way to place Radiance-aware components onto your geometry? (Having to create geometry in an old OpenStudio version with Sketchup 2017 would be a major problem, since upon updating your model to a newer OpenStudio version you wouldn't really be able to go backwards to your old OS Sketchup Plugin to do ulterior modifications...)
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What's happening to Radiance measure in OpenStudio reminds me of what Autodesk does to their products.

Mostapha Roudsari gravatar image Mostapha Roudsari  ( 2018-06-26 13:42:10 -0500 )edit

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answered 2018-06-25 15:24:57 -0500

Yes, the docs are thin. Apologies. At this point, there simply is no funding for new features or even minor bug fixes to the Radiance-related work in OpenStudio. That said, there is a great start on Radiance-EnergyPlus interoperability in OpenStudio, and the good news is since it's open source, anyone can join the fun of making it better. =)

This is actually a great place to post all these questions since they are all related. As I see it, it's not just about the OpenStudio Radiance measure, but the entire effort of embedding Radiance support in the OpenStudio SDK. There are objects, some of which could use more features, and some missing objects altogether. There is a measure that was largely meant to be a proof-of-concept, that needs some refactoring. And there is no support for spatial illuminance data visualization. Let me try and answer your bulleted questions list inline here...

1) There is an air wall construction for OpenStudio, which simply deletes those surfaces assigned the construction when the OS model is translated to Radiance. This gets around the opaque thermal zone boundary issue. As for placement of the illuminance map, I recommend getting the map within 2'-0" from the perimeter wall for small spaces (typical office), and you could float that out to 5'-0" for large open areas. This is derived from the LM-83 IESNA document which defines the sDA and ASE daylight metrics.

2) You’re still stuck with rectangular map areas, unfortunately, as the OpenStudio illuminance map object (and EnergyPlus' object) only support that. Radiance has no such limitation, and I could see one making tool(s) to generate arbitrarily-shaped maps, and other tools to visualize the spatial illuminance data.

3) There is no published measure to do this, but you are right, the SDK would fully support this. I have done something like this internally for a very specific project, and it's so rough I can't even think about publishing it, but you get the idea. The daylighting control and illuminance map objects in OpenStudio all have the methods in the SDK needed for creation, placement, sizing, setpoints, and connections (e.g. to thermal zones).

4) DView was willfully chosen as a replacement for Results Viewer even when it was known that DView did not support illuminance map data. So I don't see its lack of support as a point of concern to the team, unfortunately. I think the right answer going forward will be to develop something else entirely, perhaps something that supports arbitrarily-shaped maps. I believe there are examples of tools like this in the Ladybug Tools ecosystem.

5) The OS Radiance measure doesn't calculate ASE because we were trying to develop something that plays nice in a large-scale analysis framework, and the mechanics behind ASE dictate a whole extra set(s) of matrices for the daylight calculation, and we were already hitting issues with speed, memory, and data storage with complex multi-space models as it ... (more)

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On point 3, I have a measure which adds illuminance maps with a specified grid spacing to each zone. It brings the first grid point in from the walls by half a grid size.

This only works for rectangular orthogonal spaces and will extend the map outside the walls if you have a non-rectangular space. This will probably give false results (my first attempt placed grid points on the walls and this had the issue described in point 1). It would probably be possible to make a more sophisticated one by stitching maps together. Otherwise need to work outside OS I guess.

bobw gravatar image bobw  ( 2018-06-25 21:47:48 -0500 )edit

I am using a custom app to visualise illuminance data but it is extremely basic and needs a lot of work. It also needs post-processed data. If it gets to a stage where it is useful I'll post.

For custom metrics I post-process.

bobw gravatar image bobw  ( 2018-06-25 21:51:57 -0500 )edit

I was wondering why it's still necessary to add illuminance map in a space if daylight control provide from the daylight sensor? Am I missing something?

I suppose illuminance map is still necessary for the daylight metrics.csv file?

BORM gravatar image BORM  ( 2018-08-01 15:07:24 -0500 )edit

Yep, you just answered your own question. Spatial daylight info is needed for some of the daylight metrics, and honestly, anyone taking the time and trouble to use Radiance for the daylighting info is likely interested in more than just what's happening at the control point, so the measure expects the maps to be there.

rpg777 gravatar image rpg777  ( 2018-08-01 17:48:15 -0500 )edit

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Asked: 2018-06-25 14:34:11 -0500

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Last updated: Jun 26 '18