1. Mastering Autodesk Revit MEP 2016
CHAPTER 12: Lighting

2. Efficient Lighting Design
Spaces
Must be modeled properly for accurate lighting calculation
Upper limit defined correctly for proper volume calculation
Interact with appropriate bounding elements (ceilings, walls, floors)
Fixtures must be included within the boundaries of the space for calculation or have an active Room Calculation Point
Space properties provide important lighting data
To model lighting efficiently, it is important to understand how lighting fixture families interact with the engineering space objects in your model.
Fixtures must be included in a space in order for the space to calculate lighting levels based on the photometrics of the fixture. Proper space modeling is essential to accurate lighting modeling. Linked files can be set to define the boundaries.

3. Efficient Lighting Design
Lighting Analysis
Lighting data in Space objects is based on photometric data in lighting fixture families
Volume of spaces must be calculated
Set for entire project
Revit MEP has the ability to calculate lighting levels based on the photometrics of the fixtures used. The data is contained in the Space objects that encompass the fixtures. Volume calculation of spaces must be turned on in the project in order for lighting calculations to work.

4. Efficient Lighting Design
Lighting Analysis Schedule
Space schedule with lighting properties displayed
Create a calculated value in the schedule to show difference between Actual Lighting Level and Required Lighting Level settings
Conditional Format can be used to give a visual display to the difference
You can use the power of schedules in Revit as a design tool to determine the types of lights to use in certain spaces. A space schedule can be created to help determine if the actual lighting levels based on the fixtures meets the required levels that you can define for specific space types. A schedule key can be used to assign required lighting levels to space types. A calculated value in the schedule can be combined with a conditional format to give a visual indication of the difference between actual and required levels.

5. Hosting Options for Lighting Fixtures
Ceiling Lights
Ceiling Hosted
Requires an actual ceiling object modeled in your file
Face Hosted
Can attach to any 3D face
Default placement is to a Vertical face
Reference planes are an alternative to ceilings but only as a last resort
Reflected ceiling plan view for placement
There are a few different ways that you can place lighting fixtures into your model. Families can be created to be hosted by specific model elements, such as ceilings and walls, or they can be face-hosted or non-hosted. Face hosted is the most common type of hosting option because it allows you to host your lights to a 3D face within a linked file. Face-hosted lighting families can be hosted to a reference plane when a ceiling has not yet been provided in the architectural model.
Lights should be placed in a reflected ceiling plan view to attach them to the ceiling face.

6. Hosting Options for Lighting Fixtures
Sloped Ceilings
Face-hosted fixtures follow slope of the ceiling
Display of fixtures inconsistent between sloped and flat ceilings
Fixtures hosted by Work Plane option with Always Vertical setting are a poor substitute
Look good in plan view, but inaccurate in model
Display of only model lines in fixture family is one option for sloped lights
One of the main challenges to placing light fixtures is in dealing with sloped ceilings. The issue is that the fixtures do not display the same in plan views when they are in a sloped ceiling as they do on a flat ceiling. Using Work Plane hosting with the Always Vertical setting will display properly in plan views but is not an accurate model representation because the fixtures do not follow the ceiling slope.
Fixture families that display only model lines that outline the boundaries of the fixture is one option for consistent display.

7. Hosting Options for Lighting Fixtures
Areas with No Ceiling
Non-hosted fixture types can be used
User input and management of fixture elevations
Face hosted can be used if a reference plane is provided
Face hosted can be used and hosted to a nearby level
Fixture instances offset
Level-hosted fixture family placed with user-assigned mounting height
Face-hosted fixture families can be used in areas that do not contain ceilings. The families can be hosted by reference planes or levels. They can also be hosted by structure other than a ceiling object.
Non-hosted fixture types work well in this situation as well. They require manual input and management of their elevation.

8. Wall Mounted Lights and Switches
Wall Lights
Face-hosted families do not have Maintain Annotation Orientation setting
Annotation symbols will not display when hosted to vertical face
Model lines to represent symbol
Use of non-hosted families requires manual coordination with walls
Switches
Face hosted is best option for model coordination
Manual coordination with wall openings still required
Face-hosted family with model lines used as “symbol”
Face-hosted families for wall-mounted lights can be difficult if you choose to display wall lights with symbols. The parameter that allows for display of nested annotations when the family is placed on a vertical face does not exist in lighting fixtures. One option to overcome this is to draw model lines in the fixture family that display when the fixture is wall mounted.
Face-hosted families should be used for switches. They will stay attached to their host, eliminating the need to move them when walls move. However, if an opening is placed in the location of a switch, the switch will lose its association to the host.

9. Site Lighting Site Plan Linked Civil CAD file
Manual placement to align the site with building model
Non-hosted families for easy offset to allow for changes in topography
Although there is no Revit for Civil engineering, you can create a site plan using Civil CAD or topography modeled in Revit. It’s best to use non-hosted lighting fixture families as you can place them at the ground level and offset them as needed to account for changes in topography. Linking in a Civil CAD file will give you the necessary information for placement of your site lighting fixtures.

10. Site Lighting Site Lighting Analysis
Rendering can be used to determine light output of site lighting fixtures
Lights can be grouped to reduce burden of rendering and reduce rendering time
Sun settings can be applied for accurate site representation
Because a site is not enclosed, you cannot use a Space object to generate lighting calculations for site lighting. The rendering tools in Revit MEP can be used to get a visual representation of the light output from you site lighting fixtures. This will help you determine if fixtures are spaced properly and are providing enough coverage. Using the option to group lights allows you to eliminate non-site fixtures when rendering, which reduces rendering time and the burden on your processor.
Sun settings ensure that you are providing an accurate representation of the site in terms of project location and time of day.