Solved: Insight 2018 - different result shown when same analysis was performed

Anonymous · ‎05-28-2019

I tried to do sDA & illuminance analysis with Insight 2018 for Education. I want to show how the surrounding buildings affects the daylight received by a building. Therefore, to include the neighbour buildings is important. I did that by placing them as mass and create mass floors, as I read somewhere that Insight will only take consideration those with floors or mass floors. Then, I run analysis for level 5, 15, 25, and 35 to see the difference.

After a lot of trials and errors, I see a pattern that makes me really confused.

So, if I run an analysis right after creating the energy model (without saving the Revit file), it will show a really low amount of light getting into the building (at first I was happy when seeing this result on level 5, because that means my assumptions that level 5 will be overshadowed by other buildings was correct). But then, level 35 shows similar result, which is really strange as my building is located near equator, in a very hot&humid tropical country. (I have checked the DNI and DHI showed in Insight settings for Illuminance analysis at a specific time & date, and it showed exactly the same numbers as weather data I downloaded from Autodesk Green Building Studio : around 700-900 in the afternoon all year, with clear sky for most of the time).

However, the next time I re-run daylight analysis (when the project had been saved) with the same energy model without changing anything, the sDA and illuminance for all of those floors showed totally different result. In the new result, all of them received a really high amount of daylight. Which seems to make sense for the higher levels (level 35), but not for level 5 and 15. This means all those masses surrounded the buildings were not even counted into the analysis.

Could anyone tell me what I did wrong? Any kind of help will be really appreciated.

Thanks.

scheerd · ‎05-28-2019

Hey there.

Cool analysis, and I'm glad to help.

One thing to know first is that the Energy Analysis engine and Revit model export is a different process than the Lighting Analysis engine and export. Our teams work together, so we have them pretty well coordinated, but there are some differences that might be showing up for you.

The Energy Analysis model that is exported to EnergyPlus or Doe2 can be validated with the Energy Model view that you sent the image of. For energy results, the Masses that have 'mass floors' as you mention adding are considered to be part of the energy model building area, so they will lead to energy use in the results. In the Energy Model view they can be seen with colors like green or blue. Anything that is just considered shading is a gray color. No need to add mass floors for buildings that are just for overshadowing.

The Lighting Analysis model uses an export of the geometry visible in the '_InsightLighting Model View', which may be different from the Energy Model view geometry. Anything visible in the 'InsightLighting Model View' will be exported to the Rendering engine that we use for Lighting analysis. Check that view to see that the overshadowing elements are on or off. Also check that to see that any schematic mass elements of your main building are not on, as they will block the windows. Best to review that view with a 'Realistic' Graphics Display style so you see it with the same 'Appearance' materials properties that the Rendering engine uses.

As some of your overshadowing buildings are not simple masses, but have mass floors, they have have materials that are partially transparent or something. Check the materials used for the masses. The 'Appearance' property of the materials is the one used by the Rendering Engine (not the 'Graphics' properties).

Also know that for the sDA and Daylight Autonomy analysis types, the 3D views have a different visualization of results than the plan views. The 3d views show number of hours meeting the thresholds, while the plan views show pass or fail for a number-of-hours-threshold.

If my description here doesn't clarify for you, feel free to send the model to david.scheer@autodesk.com for review.

Also be sure you have the latest Insight addin, as we released a significant update a few weeks ago. You should be using at least v4.01 (showing in the Lighting dialog bottom left corner).

Anonymous · ‎05-29-2019

Hi David,

Thanks very much for your prompt reply, it was really helpful and cleared up a lot of doubts I had before.

According to your explanation, I removed the floor masses in the surrounding buildings (as I only need them for overshadowing my building) and I fixed the "_InsightLighting Model View". Now the results make more sense!

So, if my sole purpose is only to get daylight analysis result, do I still need to create Energy Model beforehand? And is there any way to display pass or fail of both sDA and ASE in floor plan?

scheerd · ‎05-29-2019

No problem.

No need to run the energy model first, they are separate processes.

The Plan and 3d views should both show pass/fail for both. Remember that the sDA metric is very complex (based on IES LM83), so read it carefully. There are also 2 recognized ways of passing 'both'. LM83 specifies that if a Room fails ASE for more than 20% (or 10% if you use the strict interpretation) of its area, the whole Room fails even if the building overall has less than 20% of the total area over the ASE threshold hours. In Lighting we offer ways to assess both. In the Summary dialog, if there is a '*' next to the results, you can click on that to get the alternate 'whole building ASE' method. The Plan views show 'both' using the strict Room-based rule.

David

scheerd · ‎07-18-2019

Important notes about changes to handling of glazing materials for Insight Lighting v4+ are available at the post below:

https://forums.autodesk.com/t5/lighting-solar-analysis-forum/critical-update-glazing-materials-for-l...

Insight version 4.031 is available here:

When updating to this new version, be sure to check your Glazing materials per the post above

https://insight360.autodesk.com/oneenergy/Landing/Download