Revit daylight analysis

From TOI-Pedia


During this workshop we are going to create a daylight analysis and solar analysis with Autodesk Revit.

Aamelden bij Autodesk 360!
Internet verbinding maken!
To create a Revit daylight analysis, you need to log in to Autodesk 360 using your Autodesk account. You can use the username and password that you used to download Revit from the Autodesk Education website.

Because a daylight analysis is calculated on the Autodesk 360 Cloud Servers, you need to have a working internet connection.

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Lux Units

Illuminance is a measure of how much light falls on a surface. It is useful for determining whether or not there is enough light to perform different activities (like reading, office work, drafting etc.). In Autodesk Revit illuminance is measured in lux or footcandles (1 footcandle = 10.7 lux). During the workshop we will use lux.

You need approximately 50 to 1000 lux for activities inside a building depending on the activity. An illuminance rendering shows you whether your lighting design meets the requirements of the space, and it also helps you understand how much of this light you’ll be able to get from daylighting.

For light to be reflected off of an object (luminance), it has to have light illuminating it in the first place. In lighting and daylighting design, ‘Illuminance’ is one of the quantitative measures we are interested in, because this is the light that makes the space usable by people with eyesight. This is the light that illuminates a desktop so we can see our work, a white board so we can read drawings, a hallway so we can navigate without bumping into walls and people.

  • Less than 100 lux is insufficient daylight
  • Between 100 lux and 2000 lux is useful daylight, but keep a minimum of 300 - 500 lux.
  • 500 lux (some low contrast, color judgment tasks). Activity: Computer work, reading & writing, general offices, retail shops, kitchens.
  • 750 lux (good color judgment, inviting interior.) Activity: Drawing offices, chain stores, general electronics work.

Importing a Rhino file into Revit

Rhino export

Export selected
  1. Make sure you only draw solids geometry in rhino, select all the geometry you want to export.
  2. Go to menu export selected. Select export as ACIS (.sat), in the pop up menu that follows select Default.

Rhino export sat.jpg

Tip: Make sure you import the geometric data needed for the Revit daylight analysis.

Revit import

Import model into Revit
Import options
  1. Open a Autodesk Revit Project
  2. Go to the Insert tab, Click Import CAD.
  3. In the Import CAD Formats dialog, navigate to the folder that contains the .sat file to import.
  4. Select the import file.
  5. Specify the import options. See Import Options for CAD Formats and Vasari Models. If you choose the option (Origin - Origin) the location of your model will have the same origin as in Rhino. Don't forget to check the scaling in the model.
  6. Click Open. Now you will load the solid geometry from Rhino into Revit.
  7. If you choose to manually place the imported data, it displays in the drawing area and moves with the cursor. Click to place the imported data.

N.B. If the import scale isn’t right try looking at the Units used in your Rhino model. In Revit you can go to the Manage tab, Click Project Units.

Set Revit Levels for analysis

Rhino model in Revit
Rhino model in Revit with two Levels
Select East elevation
Unpin the imported model to move it
Move bottom the model to Level 1
Set Level heights
New Level heights
Correct Project model

Now you have imported your Rhino model into Revit. The next step is to change the levels. 'This is an important step to create a correct analysis!

  1. Go to your Project Browser, Elevations and select East. In the East elevation you see your imported model and two Levels.
  2. Select the imported Rhino model. If the model is pinned, unpin it by clicking the pinn element. Now it will get a red cross beside it.
  3. Select the object.
  4. Next step is to move bottom the model to Level 1. Go to the Modify tab, Click Move. First select the bottom part and then the Level 1. Import model into Revit
  5. Next adjust the Level heights. Set Level 1 to -4800 mm and Set Level 2 to 0 mm.
  6. Now the Rhino model is properly imported into Revit.

Set Location

Set location in Revit
Location Lange Voorhout, Den Haag

When you create a project it is possible to specify the geographic location using the street address or the latitude and longitude. This is useful for generating location-specific shadows for views that use them, such as daylight studies. The location provides a basis for weather information, which is used during daylight analysis.

To specify the project location, Click Manage tab > Project Location panel > Location.

You can also access this dialog from the Energy Settings dialog. When your computer is connected to the Internet this dialog displays an interactive map through the Google Maps mapping service.

Until you specify a different project location, the location is set to the longitude and latitude of the major city specified by Revit for your locale.

For the Project Address, enter the street address, city and country. Enter: Lange Voorhout 74, 2514 EH Den Haag.

Use the following tools to adjust the map as needed:

  • Pan. When you place the cursor over the map, the cursor changes to a hand, and you can drag the map to pan the view with the Left Mouse Button (LMB).
  • For Zoom, Double Click Left Mouse Button (LMB). If you zoom in the satellite imagery will be shown.

Set True North

Set plan view
Set orientation to True North
Set rotate start
Rotate to True North - 62 degrees
Model is set to True North

You can rotate a view to reflect True North (instead of Project North, which is the top of the view).

Rotating a view to True North ensures that natural light falls on the correct sides of the building model and that the sun’s path through the sky is accurately simulated.

Project North
The 'north' side of your model, not necessarily the true north. Because it's inconvenient to have to work in a model that is slightly rotated, Revit defaults to a convenient north that aligns with vertical in the drawings.
True North
The true direction of north in relation to the model and its location.

To change the True north and rotate it in relation to the project north:

  • First you have to set your Plan View to True North orientation. Activate the Plan view, select it and go to the Properties Panel. Set Orientation to True North.
  • Then go to Manage Tab, Project Location Panel and click the Revit-Project Position.png (Position) fold-out and choose Revit-Rotate True North.png (Rotate True North). The Rotate Tool is automatically activated. Use it to rotate the Plan so it aligns with your True North.
    1. First point the rotate tool to the top, it will automatically snap there if you move your mouse. Then Click your left mouse button (LMB).
    2. second move your mouse to the right, 62 degrees (this is in relation to the given location file - week 3). And Click your left mouse button (LMB).
    3. Now the True North is set.
  • To switch a Plan View back so the Project North is up, select the view and set Orientation back to Project North.

Sun Path

Sun Path
Use project location for sun settings

The sun path is a visual representation of the sun's range of movement across the sky at the geographic location you specify for a project. The True North also will be made visible. This gives you the option to check if your north is set correctly.

  1. Go to a 3D view.
  2. On the View Control Bar, click Revit 2011 Sunpath icon.png (Sun Path) to turn it on.
  3. In the pop-up screen, select: Use the specified location, date, and time instead.
  4. On the View Control Bar, click Revit 2011 Visual Style icon.png (Visual Style) to change the visual style.

Create Camera for daylight analysis (Illuminance Renderings)

Create Camera
deselect Perspective
Place Camera and target point
Change Crop Region

It's recommended to create a new 3D view (Camera) for the daylight analysis of your design.

  1. Select a Floor Plan Level view or the default 3D view.
  2. In the Ribbon, open the View tab. In the Create panel, click the arrow under 3D View and click Camera.
  3. Before placing the camera, it is very important you deselect Perspective to create an orthographic 3D view. This means that the camera is actually a PLANE that measures illuminance values parallel to the direction it’s pointing, NOT a POINT that perceives the scene like the human eye (or camera).Create Camera
  4. Click in the drawing area where you want to place the camera itself. Don’t worry about placement of the camera target point.
  5. After placing the camera, the camera view will appear. Use the view cube to rotate the camera to the TOP view. This ensures that the camera is looking straight down. Revit viewcube top.jpg
  6. Change the Crop Region by adjusting the blue dots with your left mouse button (LMB). Make sure the Crop Region is visible in the Extents section of the camera Properties window.

Creating a daylight analysis (illuminance)

Create cloud render
Illuminance Settings - date/time
Set Sky model
Set Units to LUX & select Automatic and Logarithmic
3D view render 21 December
Top view render (orthogonal) 21 June
  1. From the View ribbon, select Render in Cloud.
  2. Click continue.
  3. Select a 3D View or the new 3D TOP View with your orthogonal camera for the illuminance rendering. The 3D views in the dialog box correspond to the 3D views you created in your Revit project.
  4. For Output Type, select Illuminance.
  5. For the Image size, choose Medium.
  6. After selecting Illuminance, you will be prompted to select the Location/Date, Sky Model, and Legend Settings.
  7. Set the date and time to 21 June 2104 and 21 December 2014, 13:00 P.M. (13:00 uur). The location for the illuminance rendering is always taken from the Revit Model Location.
  8. Keep the Sky Model on Perez All-weather Sky. The Sky Model tab features 6 different sky models for the illumination rendering, and also allows you to specify the sun’s intensity (irradiance).
  9. In the Legend tab, Set the Units to LUX.
  10. In the Legend tab, select Automatic and Logarithmic.
  11. Click Start Rendering. If you select the option: E-mail me when complete. Then you will receive a notice when the render is ready.
  12. Go to Render Gallery to view and download your render.
  13. You will be re-directed to your online Autodesk 360 Gallery through a web-browser.

Go to your latest renders or look at all your renderings. Top view render (orthogonal 21 June)

Click Action to Download your daylight renderings. Retry the download if it doesn't start. Top view render (orthogonal) 21 June

Creating a Solar Study

Revit Sunpath and Shadows
Sun Settings

In this exercise, you create an animation of the solar activity at a particular place and time in order to study the light and shadows that affect the building site.

First we create a new camera.

  1. Go to a upper level, like Level 2.
  2. In the Ribbon, open the View tab. In the Create panel, click the arrow under 3D View and click Camera.
  3. Click in the drawing area where you want to place the camera itself
  4. Click to place the camera target point (usually somewhere in or near your building)
  5. Open the new camera 3D view.
  6. You may want to use the Navigation Wheel to fine-tune the position of your camera

Now we can set this view to create a Solar Study.

  1. On the View Control Bar, click Revit 2011 Visual Style icon.png (Visual Style) and in the pop-up click Graphic Display Options.
  2. In the Graphic Display Options dialog:
    • Under Shadow, verify that Cast Shadows is selected
    • To control the Shadow contrast, you may change the Shadow value under Lighting. The default is 50, lower values result in smaller contrast between bright and shadow areas. Set it to 30 for now.
  3. On the View Control Bar, click Revit 2011 Sunpath icon.png (Sun Path) and in the pop-up click Sun Settings.
  4. In the Sun Settings dialog, select Single Day.
  5. In the Settings column, for Location, click the ... button to select a location. Type the name of the town or city to locate it on the map. Click OK. If you have set your Location at the start of your project, this is not necessary!.
  6. Select a date and time.
  7. For Time Interval, select 15 minutes.
  8. Click the Save Settings button and specify a name for these settings as a preset. Click OK
  9. Click OK.
  10. On the View Control Bar, click Revit 2011 Sunpath icon.png (Sun Path) and select Sun Path On.

The solar study animation is stored and can be exported as a movie. It is also possible to export a single image of the solar study.

Save Solar Study as a movie

Create movie Solar study
Create movie Solar study

To export the animation to a movie:

  1. Click The Revit Application Button, Export, Images and Animations, Solar Study.
  2. Select All Frames. Or depending on the time range and interval, you may have to change the Frames/sec setting to something suitable. Your animation shouldn't be too fast, nor too slow.
  3. For the Dimensions, choose a width of 1024 for a medium resolution movie.
  4. Click OK.
  5. In the Export Animated Solar Study dialog, click a suitable location, and click Save. (saving your movie as an AVI file)
  6. In the Video Compression dialog, for Compressor, select Full Frames (Uncompressed), and

click OK.

The animation is created and the AVI file is saved.

Create single image Solar Study

Rhino model in Revit
Rhino model in Revit
  1. Click The Revit Application Button, Export, Images and Animations, Solar Study.
  2. Set name and location for the image.
  3. Select Current Window to export your view.
  4. Set resolution and Format, like JPEG etc.
  5. Click OK, to save the image.
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