This exercise shows how to create a 3D model for a parametric tee fitting. A model is the graphical representation of a parametric part. In the Content Builder, a model consists of various features that have specific relationships to each other and that define the behavior of the parametric part. Some features require that you create simple shapes or points, while others require an extrusion or path. Some represent visible geometry, and some help you to position geometry precisely on a part. You can modify features to refine and improve your parts over time.
Dataset
Exercise 2: Creating a 3D Model for a Parametric Fitting | 49
To access the dataset that corresponds to this exercise, open Content Builder, and in the Getting Started
dialog, browse to Tutorial Pipe Catalog\Tees Datasets\Tutorial Tee L03 E02. Click (Modify Part Size).
Establish a work plane
1 In the part browser, expand Modeling.
2 Right-click Work Planes, and click Add Work Plane.
The Create Work Plane dialog is displayed. A work plane is an infinite plane related to one or more features of a model. Work planes provide a defined place in space from which to build a model. You must use at least one work plane to add parametric geometry.
3 In the Create Work Plane dialog, click Top, and click OK.
The Top Plane is created in Work Planes and is represented by a 750 unit x 750 unit square in the modeling area. The square is displayed to help you visualize the work plane. The actual work plane has no boundaries. You do not need to keep your model geometry within the 750 x 750 square to construct a valid model.
Add geometry
4 In the part browser, expand Work Planes.
5 Right-click Top Plane, and click Add Geometry ➤ Line.
6 At the Pick start point prompt, enter 0,375, and press Enter.
7 At the Pick end point prompt, enter 375,375, and press Enter.
8 Press Enter to end the command.
A line is added halfway across the middle of the 750 x 750 square to represent the X axis orientation for the part. The location of the line was selected for ease of modeling. In subsequent steps, this line is referred to as segment 1.
9 Repeat steps 6 through 9 to add a second line, entering a start point of 375,375 and an end point of 750,375.
In subsequent steps, this line is referred to as segment 2.
10 Repeat steps 6 through 9 to add a final line from 375,375 to 375,0.
In subsequent steps, this line is referred to as segment 3.
TIP Creating the model using 3 line segments instead of 2 gives the model more flexibility for modification in the future. For example, you could change the angle of one or both branches to an angle other than 90 degrees.
11 To help control parametric resizing, make the center point a fixed point:
■ In the part browser, expand Top Plane.
■ Expand Geometry.
The geometry of your model is displayed in the same order you created it; therefore, the second point is the center point.
■ Right-click the second Point 2D, and click Fixed.
Exercise 2: Creating a 3D Model for a Parametric Fitting | 51
In the modeling area, the color of the center point changes to green to indicate that it is a fixed point. (You might need to zoom in to see the change in color.)
Add constraints
12 In the part browser, right-click Top Plane, and click Add Constraints ➤ Perpendicular.
13 At the Select first geometry prompt, select segment 1 in the modeling area.
14 At the Select second geometry prompt, select segment 3.
15 Repeat steps 13 through 15 to add a perpendicular constraint between segments 2 and 3.
16 In the part browser, expand Constraints.
Notice that 2 perpendicular constraints have been added to the existing coincident constraints.
Coincident constraints were created when you added the 3 line segments, each of which is constrained by 2 points.
NOTE By constraining the part in this way, only the outermost points are free to move, and their remaining movement is restricted to a collinear path. When you add constraints, the Content Builder displays messages that indicate the degree of freedom remaining in the part. The degree of freedom is the maximum number of remaining constraints you can apply to the model. Using fewer than the maximum number of constraints is adequate for most parts. A rule of thumb is to use a minimal set of constraints and dimensions to achieve the parametric behavior required for your part.
Add dimensions
17 Use dimensions to set the length of the tee segments:
■ In the part browser, right-click Top Plane, and click Add Dimension ➤ Horizontal Distance.
■ At the Select first geometry prompt, select the left point of segment 1 as shown in the illustration below.
TIP For best results, select the X that marks the point, rather than the center of the point itself.
The center of the point might be too close to other model geometry for you to select it cleanly.
Use care when selecting points, zooming in and out as necessary.
■ At the Select second geometry prompt, select the fixed point in the center of the model.
■ In the modeling area, select a location for the dimension similar to that shown below, and enter 250 for the dimension value.
The part length resizes because the dimension controls the actual length of the line. The free point on the end of segment 1 moves to adjust to the new length.
18 Repeat step 17 to add a horizontal dimension to segment 2 and a vertical dimension to segment 3. Enter 250 for each of the dimension values.
Dimensions are added for the 3 tee segments. Next, you add circular profiles to use in creating cylinder shapes for the tee. By adding the cylinders, you make the tee a 3D model that represents a valid part.
Add profiles
19 In the part browser, right-click Top Plane, and click Add Profile ➤ Circular.
20 At the Select center point prompt, select a point outside the work plane.
21 At the Select radius prompt, enter 75 and press Enter.
The circular profile is added so that the profile geometry can be applied to tee segments in a later step. Neither the location of the profile in the modeling area nor the size of the radius is
Exercise 2: Creating a 3D Model for a Parametric Fitting | 53
critical to this process. As a completed parametric part, the tee will support resizing of the cylinders.
22 Repeat steps 20 through 22 to add a second circular profile with a radius of 50.
The second circular profile is added.
Next, you hide the dimensions to simplify the selection of model components as you complete the 3D model.
23 In the part browser, under Top Plane, expand Dimensions.
24 Right-click LenA1, and click Visible.
25 Repeat the previous step to hide the dimensions for LenA2 and LenA3.
Add modifiers
26 In the part browser, right-click Modifiers, and click Add Path.
27 At the Select path geometry prompt, select segment 1 in the modeling area.
28 At the Select start profile prompt, select the larger of the 2 circular profiles.
29 At the Select end profile prompt, press Enter to accept the same profile for the end of the path.
Using the circular profile, a path is swept along the first segment.
30 Repeat steps 27 through 30 to add a path to segment 2 using the larger of the 2 circular profiles.
31 Add a path to segment 3 using the smaller of the 2 circular profiles.
Swept paths are added to segments 2 and 3 to complete your 3D model.
32 Click View menu ➤ 3D Views ➤ SW Isometric to view the 3D model.
33 Click (Save Part Family) on the part browser toolbar.
In this exercise, you created a work plane and added geometry for a non-reducing tee. You added lines to represent the segments of the tee, applied constraints and dimensions to achieve the parametric behavior required for your part, and added cylinder shapes to create a true 3D model. Next, you add connectors and define the parametric sizing behavior for the part.