AUGIWorld Magazine - September/October 2008 - (Page 19)

Figure 4: A simple formula in an archtop window family makes the arch fit correctly. reference plane jumps out of position before you have tied half of the extrusions in your family to it. As you proceed with making content in your family, check every possible change to make sure that things behave the way you expect under all possible conditions. Test, test, and test again as you develop your family structure. Use the Load into Projects tool at the bottom of the Family Editor Design bar to put your family in a project environment for testing. Try your best to “break” your family before someone else does during an important deadline. your family so you can specify rather than draw them in the family editor. Curved beams and window trim are examples of sweeps. As a general rule, keep each 3D piece you create as simple as possible, and combine them to make complex objects. You can often use void geometry effectively to shape simple solids in creative ways. Take a look at any baluster family; there are voids at the top and bottom to make them fit stairs. The nesting urge You will see Width as a parameter in the Family Types dialog. Each Family Type in a door family will have a given value for Width. You will quickly get used to creating named parameters to run the dimensions that control the placement of named reference planes to make your family change shape and size. Parameters also control material, visibility, or appearance of parts of your family, and give you values you can schedule. Follow the formula The Family Types dialog lets you provide a Formula for each parameter in your family file. This way you can have one value relate to or drive another. Width can be a proportion of Length, as a simple example. When you get a little experience, you can create Yes/No parameters in your family and control them with If/Then conditions. For instance, if a shelf length is greater than a certain value, a support can automatically appear in the middle of the shelf. Formulas take a bit of time to work out correctly, but they make placing and adjusting your families quick and easy for the user. What about the modeling in a family? Is there a preferred method, or things to avoid? Well, you make 3D model content by using Extrusions, Sweeps, Blends, Revolves, and Swept Blends. All of these consist of 2D profiles that are moved through space or combined in space. You will use Extrusions the most and they are the simplest. You can extrude in any direction, so you need to be able to work Figure 6: Families within families are not all that hard to control. sideways or at other angles, and you will need to know how to tions of extrusions. There is a parameter set a Work Plane. Named reference planes type available in the RAC 2009 Family edican make this easier than otherwise. tor called that lets you asSweeps nearly always mean that you will sign the types within a nested family. That draw a path in one view and the profile in way you can cycle door fronts in a kitchen another view. You can load profiles into layout, for instance, without having to create a separate cabinet family to hold each door type. This is by no means an exhaustive look at creating model families; we could talk for days about the different ways to create your own content for Revit. I hope you have gotten a few ideas for ways to expand your repertoire! Chris Fox is the Revit editor for AUGIWorld, and has written numerous articles on Revit Architecture, Revit Structure and Revit MEP. He has written Autodesk Official Training Courseware for Revit Architecture and Revit Structure and Introducing and Implementing Revit Architecture 2009, published by Autodesk Press. Chris recently moved from the US to Australia, and is leading training classes in Revit through corporate, university and technical school contacts there. You can reach him at lcfox@archimagecad.com. 19 Into the void You can insert one family into another; this is called nesting, and while it sounds complex it can simplify your modeling while creating families and open up options while placing them. In the host family you simply load in the other families you want and place them as components. Consider doing this even for relatively simple families, such as casework and cabinetry, which themselves are really just combina- Flex for the crowd Whenever, and I mean whenever, you use the Family Types dialog to make a change in a family file you are editing, check what you have just done. When you set up reference planes to define Height and Width for a couple of different sizes of a window or door, to stay with our example, enter in the appropriate values for a Family Type and click Apply. Watch what happens before you create the next Family Type, then, click Apply for that type. This is called flexing, and you can and should do this even before you start modeling. It will save you time and grief to find out that a Sep/Oct 2008 Figure 5: With Voids, what you don’t see is what you get!

Table of Contents Feed for the Digital Edition of AUGIWorld Magazine - September/October 2008

AUGIWorld Magazine - September/October 2008 Contents The CAD Manager 2008 Salary Survey Save Time with Impression Blocks In the Family Way Structural Stairs Autodesk University 2008 Preview Action Recorder How to Embrace Third-Party Data On the Back Page

AUGIWorld Magazine - September/October 2008

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