CHAPTER 17
Creating Families

As you’re probably becoming acutely aware, having the right content will make or break a Revit project. I’m sure you’re also very aware that, other than the content Autodesk has provided and the content you downloaded from this book’s web page, you don’t have anywhere near the amount of content you need to start a project! That being said, it’s time to buckle down and dig into how Revit works, and see how having adjustable, parametric families will turn you into a Revit fan for life.

Creating a basic family
Using a complex family to create an arched door
Creating an in-place family

Creating a Basic Family

The first item we’ll tackle is how to create a basic family. We’ll start with the creation of a wall sweep and then move on to creating an arched doorway. As you become fluent with these two basic family types, you will really start to become quite fast at creating families.

You have to start somewhere. To be honest, no good family is “basic,” but some are easier to create than others. The concept is the same, however.

Essentially, a family has three fundamental components:

Reference Planes Yes, reference planes drive the family. Look at these as the family’s skeleton.

Constraints Constraints are dimensions with a parameter associated with them to give the skeleton its flexibility.

3D Massing 3D massing is locked to the skeleton. We’ll call this the skin. Corny, I know, but it gets the point across.

To get started, you need to figure out where to get started. Any family that you want to insert into a Revit model must begin with a template. Choosing the correct template, as you’ll soon discover, will make your life much simpler.

The objective of the next procedure is to start a new family by choosing a template in Revit. Follow these steps:

1. Open Revit Architecture.
2. In the Recent Files screen, click the New link in the Families row in the middle of the dialog (or click the Application button and select New Family).
3. In the Imperial Templates (Metric Templates) folder (where the family templates are stored), select Profile-Hosted.rft (Metric Profile-Hosted.rft), and then click Open.

As mentioned earlier, first you’ll notice the reference planes. A good family starts and ends with these. Next, you’ll notice some text. Revit adds advice in each of its family templates. After you read the advice, you can delete it. You’ll do that in a moment, but first let’s add reference planes to the family.

Adding Reference Planes to a Family

The one bad thing about creating a family is that you can get away with doing so without using reference planes at all. This is unfortunate, because a family made with no (or not enough) reference planes will be faulty at best. I’ve learned that lesson the hard way. Although it may seem redundant to add reference planes, I strongly advise you to use them and use them often.

The objective of the following procedure will be to offset some reference planes to create the wall sweep. Follow along:

1. On the Datum panel of the Home tab, click the Reference Plane button, as shown in Figure 17.1.

FIGURE 17.1 The Reference Plane button on the Home tab
2. In the Draw panel, click the Pick Lines button.
3. On the Options bar, set Offset to 1´–0˝ (300mm).
4. Hover your cursor over the center, vertical reference plane. When the blue reference line appears to the right of the vertical plane (as shown in Figure 17.2), pick the center reference plane. You now have two vertical reference planes spaced 1´–0˝ (300mm) apart.
5. With the Reference Plane command still running, pick the horizontal reference plane, and offset it down using the same offset increment of 1´–0˝ (300mm). Your family should resemble Figure 17.3.

These two reference planes represent the body of the sweep. The objective of the following procedure is to add two more secondary reference planes for more control over the family. Follow these steps:

1. Set Offset to 2˝ (50mm).
2. Offset the top horizontal reference plane down.
3. Offset the left vertical reference plane to the right (see Figure 17.4).

f1702.eps — **FIGURE 17.2** Adding a second vertical reference plane

With the reference planes in place, you can move on to adding dimensions to them. After you add the dimensions, you’ll add parameters to those dimensions to make your family flexible when you add it to the model.

Adding Dimensions and Parameters to a Family

We’re now looking at one of the most outstanding features of Revit. Because you can create a parametric component easily and then allow the end user to change the dimensions, you can put your company into overdrive in terms of pushing BIM through and having success with Revit.

The first procedure involves adding dimensions to the reference planes you’ve already put in place. The second procedure will add parameters to the dimensions you’ve added. Follow along:

1. On the Measure panel of the Modify | Place Reference Plane tab, click the Aligned Dimension button.
2. Add a horizontal dimension from the left reference plane to the right reference plane. The dimension should be 1´–0˝ (300mm).
3. Add a second dimension from the top reference plane to the bottom reference plane. The dimension should be 1´–0˝ (300mm).
4. Add a dimension from the left reference plane to the 2˝ (50mm) reference plane to the right.
5. Add a dimension from the top reference plane to the reference plane 2˝ (50mm) down (see Figure 17.5).

f1703.eps — **FIGURE 17.3** Adding a second horizontal reference plane downward

The next step is to make this family come alive! Because you’re in the Family Editor, when you select a dimension you can choose to add a label to the dimension. This label is tied to a parameter that can be modified.

f1704.eps — **FIGURE 17.4** Offsetting two more reference planes

To add a label to a dimension, follow these steps:

1. Press Esc twice. Then, select the top, horizontal 1´–0˝ (300mm) dimension.
2. On the Options bar, click the Label field, and choose Add Parameter (see Figure 17.6).
3. In the Parameter Properties dialog, under Parameter Data (as shown in Figure 17.7), type Width for Name.

NOTE

When you add a name to the parameter, you’re actually adding part of a formula. There is a chance that this name will be part of a mathematical expression. When you name parameters, be deliberate, and give the names some thought. Also keep in mind that the mathematical expressions built into the parameters are case sensitive. If you capitalize the first letter of each word, be consistent.
4. Click OK. The parameter is added to the dimension.
5. Select the 1´–0˝ (300mm) vertical dimension.
6. On the Options bar, click the Label field.
7. Select Add Parameter from the menu.
8. For Name, type Height.
9. Click OK.
10. Select the two 2˝ (50mm) dimensions.

FIGURE 17.5 Adding the dimensions to the reference planes

FIGURE 17.6 Choosing Add Parameter on the Options bar

FIGURE 17.7 Configuring the parameter

Choosing Instance or Type

The decision to use instance or type may be the most important decision you’ll make when creating family parameters. As you’ve noticed, when you’re modifying a family in the model (such as a wall, door, or window), you can either make a change to the single instance of the component you’ve selected, or click Type and change the component globally within the model.

When the parameter was created, either Instance or Type was selected. So, when you’re creating a parameter, you need to ask yourself, “Do I want the user to modify only one instance of this family by changing this parameter, or do I want the user to change every instance of this family by changing this parameter?”

To complicate matters, if you plan to use this parameter in a mathematical expression, every parameter in that expression must be of the same type. For example, you can’t add an instance parameter to a type parameter. Revit won’t allow it.
11. On the Options bar, click the Label menu.

Remember, if you hold the Ctrl key, you can select multiple items. The objective of selecting both the 2˝ (50mm) dimensions is that you’re going to create one parameter and put both items on it.
12. Select Add Parameter.
13. For Name, type Reveal.
14. Click OK.
15. Click anywhere to clear the selection.

With the reference planes in place and the dimensions set with the parameters, it’s time to go behind the scenes and see how these families operate by examining the family types and adding formulas to the parameters.

The Type Properties Dialog

Within the Family Editor lies a powerful dialog that lets you organize the parameters associated with the family you’re creating. The Type Properties dialog also allows you to perform calculations, and to add increments in an attempt to test the flex of the family before it’s passed into the model.

The objective of the following procedure is to open the Family Types dialog and configure some parameters. Follow along:

1. On the Properties panel, and click the Family Types button, as shown to the left in Figure 17.8.

FIGURE 17.8 The Family Types button on the Properties panel
2. In the Family Types dialog, click into the Formula cell in the Height row.
3. Type Width, and press the Tab key (see Figure 17.9).

FIGURE 17.9 The Height parameter is now constrained to the Width parameter.
4. Click into the Width value (the area in the Width row that has the 1´–0˝ (300mm) increment).
5. Change Width from 1´–0˝ (300mm) to 6˝ (150mm). The Height value changes too.
6. Click OK. The 1´–0˝ (300mm) dimensions are reduced to 6˝ (150mm).
7. Click the Family Types button.
8. Change the Width back to 1´–0˝ (300mm).
9. Click Apply. The dimensions update in the drawing area.
10. Click the New button in the Family Types area, as shown in Figure 17.10.
11. Call the new type 12˝ × 12 ˝ (300mm × 300mm), and click OK (see Figure 17.10).

FIGURE 17.10 Creating a new family type
12. Click the New button again.
13. Call the new type 6˝ × 6˝ (150mm × 150mm), and click OK.
14. Change Width to 6˝ (150mm).
15. Change Reveal to 1˝ (25mm).
16. Click Apply. The reference planes and dimensions update.
17. Change Type back to 12˝ × 12˝ (300mm × 300mm).
18. Click OK.
19. Click Save, and save the family somewhere you’ll be able to retrieve it later. Name the file Cove sweep.rfa.

Now that the reference planes and parameters are in place, you can flex the family to make sure that it will work properly when you load it into the project.

Tags: Autodesk Official Training Guide

Aug 3, 2021 | Posted by admin in Building and Construction | Comments Off