TUTORIAL R-01:

REVIT - PARAMETRIC CURVESThis Tutorial introduces the concepts of parameters, the Family Component, and the Conceptual Mass Environment. Understanding parameters and how to apply them to model components is one of the basic modeling skills required to work within BIM. Parameters are defined by variables or mathematical expressions that report information, define constraints, or adjust form. Families within Revit are components that will be inserted into the project or other family environment similar to Blocks in “Rhinoceros” or “AutoCAD” or Components within “SketchUp”. The Conceptual Mass Environment is the design template for working with complex forms and adaptive parametric concepts within Revit.

By Jeremy L Roh, Professor of BIMethodsUNC Charlotte’s School of Architecturehttp://www.jrohdesign.com/revit/

Start a New Conceptual Mass which is a Family Template that can be accessed in 3 ways within the Revit Interface.

1] From the “Recent Files” Revit Startup Screen, “New Conceptual Mass”, “Mass.rft”, and “Open”.2] From the “Application Menu”, “New”, “Conceptual Mass”, “Mass.rft”, and “Open”.3] From the “Application Menu”, “New”, “Family”, the “Conceptual Mass” folder, “Mass.rft”, and “Open”.

When starting up in Revit, by default, the Properties and Project Browser show up stacked on the left side of the screen. When working on Families and Projects, the Project Browser will continue to grow and you typically need to see as much of the Properties dialog box as you can; therefore, it is best to separate the boxes on the screen. Hold the left-click button on the blue title box and drag the Project Browser so that it docks to the right side of the screen.

Double-Left click on the “East” Elevation to switch from the default “{3D}” View to an elevation view of the Conceptual Mass Environment.

While in the “East” Elevation View, click on the “Point Element” within the “Home” menu ribbon under the “Draw” sub-section.

NOTE: The “Point Element” is only available in 3 Family Template Categories: Conceptual Mass, Adaptive Generic Model, and Curtain Panel Patterned Base.

1] Place 3 Point Elements on the Screen

2] Window around the 3 points to select them by holding the left-click button and dragging your mouse from top left to bottom right. You can also select by left-clicking on each dot while holding in the CTRL key on the keyboard.

3] In the Properties dialog box, select “Always” from the “Show Reference Planes” drop-down menu. To get the menu to appear, left-click into the white space after the word “Never” and a drop-down arrow will appear on the right side.

NOTE: Showing a Reference Plane allows us to apply dimensions and elements to the Reference Point.

Click on “Aligned Dimension” from the “Home” menu ribbon and “Dimensions” sub-section.

You can also access the “Aligned Dimension” command from the quick menu at the top of the screen or from the “Modify” menu ribbon under the “Measure” sub-section.

1] While in the “Aligned Dimension” command, left-click on the vertical line associated with each Reference Point Plane.

2] When finished, left-click on the “EQ” symbol that appears above the dimension string.

Typically dimension lines are used to dimension a final product on a construction document sheet such as a floor plan; however, in Revit, dimensions are also used to set constraints and are the link to make connections to defined parameters. The next steps will go through methods for apply parameters to the reference points to control the overall length and position of the Reference Points.

1] Click on “Align” in the “Modify” menu ribbon under the “Modify” sub-section

You will notice that when you select the “EQ” symbol, the dimension values turn to “EQ” and the center point shifted over to make the points equally spaced. Ideally, we want the center Reference Point to be aligned to the center plane on the screen (the vertical dashed line). Using the align command allows us to lock or constrain elements to other objects and references. This tool is used fairly often in Revit.

2] With the “Align” command activated, left-click the vertical dashed line.

NOTE: Always click the aligning element first.

3] Then left the vertical line of the Reference Point Plane.

NOTE: Always click the element that you want to align last.

Once the elements become aligned, a pad-lock will appear. Left-click on the pad-lock to lock it. This sets the reference point to always align with the vertical reference plane. This defines a constraint.

1] Click on “Aligned Dimension”

2] Create a dimension string being sure to snap to the vertical line of the reference point planes at each end.

Left-click on each reference point one at a time and then left-click hold and drag your mouse on the blue arrow to move each point up. We are doing this in order to be able to add a dimension string from the horizontal reference line to each horizontal line of the reference point plane.

1] Select “Aligned Dimension”

2] Add a dimension from the horizontal reference line (the dash-dot line) to the horizontal line of each reference point plane.

2] Select “Spline Through Points”

1] Select each point by left-clicking and holding down the CTRL key on the keyboard

You should be able to select each point and drag the blue arrow up and down to see the spline adjust and follow each point. Also, you will notice that all dimensions update in real-time as you move each point. This informs you that all of these items are connected; however, at the present moment, these items only adjust manually. In order to make this curve parametric, we will need to define some parameters and associate them with defined dimension strings.

To define parameters, select the “Family Types” icon which can be accessed in the “Home” or “Modify” menu ribbon.

1] In the Family Types dialog box, click “Add” under “Parameters”.

2] Give the parameter the name, “Length” and click “OK”

NOTE: All parameters need a name. You can name them whatever you would like and they can contain spaces and special characters. Keep in mind that parameters are also used in formulas; therefore, It is best practice to name parameters without using characters that would occur in mathematical expressions such as: +-/*()<>

Add more parameters and define the values as indicated in the dialog box.

1] To associate parameters with the model components, first click on “Modify”.

2] Then click on a dimension string.

3] From the options bar, you can select a “Label” which lists all the parameters that you have already defined. Select “Length” to coincide with the overall length dimension string.

Apply the defined parameters to the dimension strings as shown.

The beauty of creating parametric family components is that all you have to do is create one object, add parameters to it, and then redefine it in various types to create different iterations of the design.

1] First select the “Family Types” icon in the menu ribbon.

Select “New” under “Family Types” in the dialog box.

3] Give the Type a name. This will be the name that you can select from a drop-down box later on. In general, your family type name should be called something that relates to it’s parameters; however, for now, we will just call the first type, “Type 1”.

4] Once you have named the type, you can set the values of the family by changing the “h3”, “h2”, “h1”, and “Length” parameters. To apply the changes to that Family Type, click on “Apply”.

NOTE: The following slides are examples on variations on the type and conclude this tutorial. The next tutorial will show you have to use these splines to create complex parametric surface forms.