Avatech Tricks: Positional Representations

12 Apr, 2006 By: William Kane

Add positional representations for mechanical systems using Microsoft Excel.

Mechanical systems often have moving parts. For this reason, designers and engineers need to show machines in multiple positions. With Autodesk's positional representations, you can illustrate assemblies in multiple predefined positions. In this tutorial, I'll show you how to apply constraint overrides and create additional positional representations using Microsoft Excel. This process will allow you to create both simple and complex representations of machine motion processes.

First, you must define at least one positional representation overriding the constraints or components you wish to control using Excel. An assembly file has a master positional representation that represents the default state of the assembly. When you create a new positional representation, the master is copied.

1. In the browser, click to expand the Representations folder (figure 1).

Figure 1. The Representations folder.

2. Right-click Position, and then select New (figure 2).

Figure 2. Chose the New command.

The new positional representation is activated and nested below the master using the default name PositionalRep1 (figure 3).

Figure 3. The default PositionalRep1.

Additional representation names are incremented unless you change the name.

3. If appropriate, click the positional representation in the browser and then enter a new name (figure 4).

Figure 4. Enter a new name, such as Contracted.

4. Click the Save tool to save changes. The positional representation is saved in the assembly file.

5. Once created, you can begin overriding constraints within the new positional representation by browsing down to the constraint to modify, right-clicking on the constraint in the browser and selecting Override (figure 5).

Figure 5. Select the Override command.

6. Then you can define the type of override to apply to this constraint using the Override Object dialog box (figure 6).

Figure 6. Override Object dialog box.

7. After you have applied the Override command and selected OK, you then can change to the Representations browser by selecting the browser's style arrow and selecting Representations (figure 7).

Figure 7. Select the Representations command.

8. You'll now see all of the positional representations within the assembly (figure 8).

Figure 8. List of positional representations.

9. Next by selecting the Edit positional representation table button button, Inventor will launch Microsoft Excel.

10. Within Excel, you can add additional positional representations by adding new representation names to the name column and redefining the override values for each representation (figure 9).

Figure 9. Redefine the override values.

11. After making the additions to the spreadsheet, select Save and close the spreadsheet.

12. Notice the new positional representations now in Inventor (figure 10).

Figure 10. List of new positional representations.

Shown here are the different positional representations generated with this exercise (figures 11-13).

Figure 11. Contracted.

Figure 12. Extended halfway.

Figure 13. Fully extended.

About the Author: William Kane

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