1. Mastering Autodesk Revit MEP 2016 CHAPTER 21: Creating Devices

2. Device Geometry Category and Parameters
Several categories for device families
Part Type parameter defines more specific behavior
Lighting Device family with Switch as Part Type is able to be used in a switch system
Maintain Annotation Orientation
Important for display of nested annotation symbols on various hosts
Creating solid geometry for device families is similar to modeling equipment families only on a smaller scale. The level of detail for devices can be kept very simple to represent the components. In most cases, the geometry does not need to be parametrically controlled, but there are some families where parametric geometry is useful.
As with any family, you should first decide how it will be used in your projects. For the most part, device families should be face-hosted families, because it is likely they will be placed in walls, floors, and ceilings. Of course, there are some exceptions such as junction boxes, which you may want to put into the model without a host.
All of the device categories have the same parameters, but the options for the Part Type parameter vary depending on the category.

3. Device Geometry Geometry and Reference Planes
Minimal geometry required
Simple box can be used for many devices
Geometry not required for connectors
Reference planes define insertion point of family and origin of geometry
Geometry should be modeled in proper relation to placeholder host for face-hosted families
With the family category and parameters established, you can begin modeling the geometry of your device family.
The amount of solid geometry that you include in a device family depends not only on the object you are creating but also on how it will be used in your projects. If your intent is to only use devices so that their symbols are shown on your plans and you are not concerned with 3D visualization, you can use a simple box. This will at least give you the ability to see the location of the device in section and elevation views for coordination with things such as casework and openings.
Solid geometry is not required in order to place connectors into the family, but it gives you a good reference point for the connectors. The reference planes in the generic family templates define the insertion point of the family. The vertical plane is the center point between the left and right side, while the horizontal plane defines the front and back of the family. The insertion point will be at the intersection of these two planes.

4. Device Geometry Face Plates
Device without face plate is not visible in plan view when hosted by floor
Face Plates
Modeling face plates can help make devices visible when they might not be otherwise
Devices hosted to floor
Model lines on face plates helps to identify devices in section/elevation views
Plan
Section
Device with face plate visible in plan view when hosted by floor
Face-hosted devices should be modeled so that the geometry is inside the host or lying on the surface of the host where applicable. Be aware that if you model a solid form so that it is inside the host, the device will not be visible when the family is hosted by a floor unless the view range of the view includes the floor.
If you are creating a device family for an object that requires a face plate, the plate geometry should be modeled to the surface of the host.

5. Annotation for Devices
Nested Family Location
Placement of annotation families in device families is important to how they will display in projects
Maintain Annotation Orientation parameter can be used for face-hosted families
Annotation family can be loaded into plan view and will display when device has a vertical host
Annotation families cannot be placed in elevation views in Family Editor
Project plan view
Nested annotation with insertion point at center, located at center of device family
Project plan view
Nested annotation with alternate insertion point, located at center of device family
Although the use of symbolic lines is helpful for identifying devices in section and elevation views, these objects are typically represented in plan views by symbols. Annotation families can be added to your device families to represent them in the same manner as you would for a traditional 2D CAD project.
For face-hosted families, this is where the Maintain Annotation Orientation parameter is important. When you place an annotation family into your device family, it will only appear in model views that are parallel to the view in which it is placed in the family. With the parameter selected, you can place the annotation in the Ref. Level view of the family, and it will display when the device is hosted vertically. Annotation families cannot be placed into an elevation view when working in the Family Editor.
The annotation family that you use in a device family should be located in proper relationship to the geometry of the family so that when the device is placed into a project on a vertical face, the annotation symbol will be aligned with the device host.

6. Annotation for Devices
Parameters for display control
Multiple annotations can be nested for required rotational display
Yes/No parameters control the visibility of individual annotations
The orientation of an annotation symbol may not be correct for every instance in your projects. In some cases, the annotation may need to be rotated to display as desired. You cannot rotate the annotation separately from the device family once the device is placed into a project.
Using multiple annotations within a device family allows for displaying a rotated annotation symbol when required. Yes/No parameters can be used to control the visibility of the individual nested annotations, giving you the ability to toggle between annotations when using the device family in a project.
Family Editor
Project

7. Annotation for Devices
Parameters for offsets
Nested annotation symbols can be offset from geometry
Avoid interference with other device symbols
Display when vertically aligned devices shown in plan view
Offset parameters in annotation family associated with device parameters
Family Editor
Project
Another method for controlling annotation symbol display is to apply an offset parameter so that the annotation symbol can be offset from the actual location of the device. This is useful for situations where two devices are next to each other and their annotation symbols interfere. This can be done directly in the device family by creating a reference plane or line parallel to the plane that defines the left and right sides of the device.
You can use this same functionality to create an offset that will pull the annotation away from the device geometry. The offset plane or line can be created directly in the device family only if the family is a nonhosted type. For a face-hosted family, you need to have an offset defined in the annotation family.

8. Annotation for Devices
Parameters for Labels
Labels can be created in annotation families nested in devices
Label cannot be moved when device is used in project
Best to use parameters that can be tagged
Tag can be placed in the project anywhere near the device
The best way to have the freedom to move text associated with a device is to create a parameter that holds the value and use a tag in your project that reads that parameter. This places the information directly in your project, not embedded in the device family, allowing you to place the tag wherever you want.

9. Connectors Types and Association
Several system types available for use on any of the device categories
Type of connector determines system (circuit) that can be created when used in projects
The connectors that you add to device families will most likely be electrical connectors since these families are the types of building components for controlling systems or power distribution. There are several types of electrical connectors to choose from. The type you add should coincide with the function of the device in your projects.

10. Connectors Connector Properties Placement
Define electrical behavior and available systems
Most connector types are only for connectivity
Power connector types have properties that can be associated with device family properties
Placement
Multiple connectors can be added to a single device
Device with multiple connectors in a project
The properties of the connector are what defines the system behavior of the device family. Most of the electrical connector system types do not have any parameters for defining electrical behavior. These connectors are simply used for keeping track of connectivity between the devices and their equipment, so their properties are very simple.
Be sure to locate the connector at the insertion point of families that do not have any 3D geometry (such as equipment and motor connections). This is done by using the Work Plane placement option.
For some device families, you may have the need for multiple connectors. This may be because of different systems within the device or because the device has multiple connection points.