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Welcome to seventh part in our series on creating custom components. In this particular article we are going to take a look at Hosted versus Non-Hosted Components and what you need to think about before choosing a template for your new Family.

When we talk about 3D components in Revit, we are either talking about Hosted or Non-Hosted components. Hosted Components require a Host in order for them to be placed into a project. To prove this, open a Revit Project and try placing a door into your (blank) model world. Revit will not allow this to happen. Doors are Hosted by Walls. So without a wall, you cannot place a door.

The main advantage of hosted components is that they always retain their relationship with their host. So if you place a door into a wall and then move that wall, the door moves with it.

Now compare this to placing a piece of furniture (ie a desk) into your model. You can place a desk before you have created anything else. You don’t even need to create a floor for it to sit on.

The desk it totally independent of any model elements. All it relates to is the Level upon which it was placed. If the Level changes height, so does the component.

When you create your own components (from within the Family Editor) you have to make the choice as to whether you wish to create a Hosted or Non-Hosted component. And if you do choose to create a Hosted Component, you need to choose the Host Type.

There choice of Host Types available to you are:

• Wall based

• Floor based

• Ceiling based

• Roof based

• Face based

So how do you tell Revit which of these Host Types you require for your new component? Quite simply by choosing the appropriate template when you start creating your new family.

If you go to File > New > Family

You are presented with a variety of templates on which to start creating your new component.

All these templates vary (from each other) in TWO fundamental ways:-

Firstly…

Their Primary Category as defined by the Object Styles control panel. For example, if you choose to build a component based on an “Electrical Fixture” template….

….then you will be able to control the visibility of that component (once used in a Revit Project) by turning on (or off) the Electrcial Fixture Category from within the Visibility / Graphics Overrides panel.

And secondly….

The correct default Reference Planes and sample materials are included in the template, depending on which Host Type you require.

For example: If you are creating a new window from scratch and you choose the Metric Window Template..

…the template comes complete with a sample section of wall and a basic opening in which you can create your own window.

Summary:

Before you start creating any custom component, give plenty of thought to how you require your object to relate to it’s surrounding elements  and also to how you may need to control it’s visibility from within a Project File. The answers to both of these questions should combine to ensure you choose the correct template upon which to base your new family.