March 18, 2013

Posted on March 11, 2013 by Robert Reid, Synergis Manufacturing Solutions Engineer:
Two seldom used measuring tools found within the Autodesk Inventor software is the “Region Properties,” and “Cross-Section Analysis.” These measuring tools can be found in both the part environment, and also the assembly environment.
In the assembly environment, the part must be active.  Both tools can be used to calculate the Physical Properties (Centroid, Moments of Inertia, and so on).
The purpose of the Region Properties tool is to evaluate the area, perimeter, and the Area Moment of Inertia properties of sketch loops. All measurements are taken from the sketch coordinate system.
When the Calculate button is clicked after the selection of geometry within the Region Properties dialogue box, the following is automatically calculated:

  • Area and Perimeter: provides cumulative area and perimeter values if multiple sketch loops are selected.
  • Centroid Location: displays the X and Y distances from Sketch origin to Centroid.
  • Inertial with respect to Sketch Origin: provides Inertia Tensor and Polar Moment with respect to the sketch origin.
  • Area Moments of Inertia with respect to Principal Axes: provides Principal Moments, Polar Moment, Rotation about Z Axis, and Radii of Gyration, with respect to the Principal Axes

Region Properties:
You’ve created a small built-up section of three structural steel members, and two holes have been added to the upper plate. You want to create a section thru the first hole, and have the Inventor 2013 software calculate the Region Properties thru this section. Without using the Inventor 2013 software, manual calculations can be time consuming and labor intensive to calculate each structural member and add them together to find the Moment of Inertia (Ix or Iy), Polar Moment of Inertia (J) or Radius of Gyration (r).
Let’s take a look at the following part example:
1)      Create the Work Plane thru the hole:

2)      Create a New Sketch on the Work Plane, hit F7 to Slice the Graphics:

3)      From the Project Geometry Drop Down Panel, Click on Project Cut Edges, and select all the geometry within the perimeter of the cross-section profile:

4)      Click to TOOLS Tab:

5)      Click the Black Arrow Down on the Measure Panel:

6)      Click Region Properties:

7)      In the Region Properties dialogue box, Under Selections, Click to Add, Select all the Closed Regions on the Sketch plane:

8)      If Dual Units are required, select the appropriate units from the dropdown.
9)      Click Calculate, the Region Properties are displayed:

Cross-Section Analysis:
The purpose of the Cross-Section Analysis Tool is to provide basic (Simple) or detailed (Advanced) information about the interior of solid parts, and to analyze whether the part thickness falls within the minimum and maximum thickness settings. A corresponding cross section graphic is displayed in the graphics window.
The Simple analysis type generates a cutaway view of the part at a single section plane. The Advanced type provides a table of more detailed information on multiple section areas of the model along with a corresponding cross section graphic. Our Original Part Model:

1)      The following image shows the part after it has been Split, and the front section removed.

2)      Click on the Inspect Tab, then click on Section on the Analysis Panel:

3)      In the Cross-Section Analysis Dialogue Box you can rename the Cross-Section, Select the face to be Cross-Sectioned, and choose Advance:

Selected Face Shown:

In the Cross-Section Analysis Dialogue Box, use the Column Chooser to choose which Physical Property you would like to see displayed. Drag and drop from the Customization Box:

4)      Click Calculate to retrieve Physical Property Data:

Hopefully this was able to help you.  Let me know if there are any other topics you would like to hear about regarding designing in Inventor.
You can also take a look at my past posts on Inventor Design Accelerators:

Also check back each week because I am going to add a few more in March.
Robert Reid graduated from Middlesex College in New Jersey with a Degree in Mechanical Engineering Technology. With over 25 years of Industrial Machine Design, including Wire Drawing Machinery, Plastic Processing Machinery, & Packaging Machinery, Robert has held various positions within the workforce, including, Manager of Engineering; Sheet Extrusion Dept, Manager of Engineering, Chief Design Engineer. He is currently an Autodesk Inventor Certified Expert.