In all applications of Sefaira it is assumed that the shading you draw in the 3D model is intended to be included in your analysis model. This includes any objects tagged as shading in Revit or in SketchUp.
This can lead to the following challenges when running your model:
- The method EnergyPlus uses to account for shading in its analysis slows down the run times substantially with large numbers of shading elements. Models with more than about 200 planes start to slow down (you might expect run times to exceed a couple of minutes at this point). Models with more than 500 shading planes will crash or time out.
- In the Plugin, this slowdown can negatively impact the User Interface, which is why we limit shading planes for energy analysis there to 500.
- Sometimes you will upload elements that have been tagged as shading that you did not intend to upload and these might cause the simulation to run slowly.
To help you manage this Sefaira includes a range of features described below.
Helping you import only the shading elements you need
It’s easy to forget that intricate shading devices not only slow down the analysis when imported, they can also be studied parametrically much more easily from within the web-application.
The first step then is to make sure you only import the shading that you need from your 3D model.
Revit models contain many elements that when converted into Sefaira turn into shading planes and slow down the run. The most common of these elements are:
- Details on Shading Components
- Internal Walls
Before you upload your Revit model to the web-application, it is strongly recommended you use the “Generate Views” feature (see image below).
This generates 4 new views of your model that can be seen in the views section of the project browser:
The views hide from view all the elements that are not needed for accurate analysis and that are likely to slow your run down. Remember - all this does is generate a different view of your model - nothing is deleted!
When uploading to the web-application or doing E+ energy runs in the plugin, be sure to choose the “Sefaira Systems Analysis View (e+)”. This will automatically hide mullions and other elements which tend to add unnecessary shading to your model and slow it down.
If you want to investigate other views than the default options you can learn how here.
In SketchUp, it’s really easy to see how many shading planes are in your current view using the entity palette in the plugin. In the example below there are 720 shading planes.
You can use this feedback to sense-check your model and simplify any complex shading devices if necessary.
This detailed context, which is thousands of planes in SketchUp (and thus too plane-heavy for EnergyPlus), can be simplified to speed up the simulation and deliver analysis results.
This simplified version will run much faster!
Once your model is in, you still have a lot of control
Once your model is imported, if it contains a lot of shading planes you’ll get a warning. Don’t worry - it will still run and if possible it will finish the simulation. But it could take a while if you have a lot of shading planes.
If you want to ignore the shading planes from your model there is a control in the shading section that lets you ignore modeled shading. Selecting this option effectively turns off all the planes you identified as shading in your model for the EnergyPlus analysis.
Now you can parametrically study shading options. Look at the shading card - there are things like horizontal and vertical fins, automated external shades and internal blinds to consider. You can use the response curve feature to find the optimal configuration for these elements.
Just remember if you don’t hide the 3D model drawn shading it will be additive to any parametric shading used in the analysis.
- Mullions (in Revit) should be filtered out from the view e.g. VG and hide mullions in the current view as they will have minimum effect on the thermal performance but can add significant time to the run.
- Simplify the shading that you have drawn to geometry that is not complicated e.g. merge coplanar faces, simplify detailing to straight lines, etc.
- Remove any shading that is not going to materially affect your model results e.g. lots of context a few streets away from your building.
- Separate Context and Building Shading into individual layers/views in your model. Run with context only first to test analysis run times in the Plugin.
- Run the model without modeled shading first to get a sense of results and how they might be improved with targeted shading e.g. split up modeled shading into focus facades first.
- Use the web application's built-in shading tools rather than the modeled shading e.g. vertical/horizontal projections.
For further guidance see other Shading Tips on our Knowledgebase;
If you have any questions about shading in Sefaira Systems please contact your customer success representative.