How to Find the Center of Gravity in CATIA

Launch CATIA V5

Open CATIA V5 and wait for the main interface to load. The background shows a starry sky, and a banner at the bottom links to additional resources.

Start a new assembly design

1. Move your cursor to the top menu and click Start.
2. Hover over Mechanical Design in the dropdown menu.
3. Select Part Design to create a single part. To follow the top-down approach in this guide, select Assembly Design instead.

Insert a part and sketch the first cylinder

1. In the assembly workbench, go to the Insert menu, choose New Part, and insert it under the current product.
2. Confirm that the new part appears in the product tree on the left side of the screen.
3. Select the new part (for example, Part1) in the product tree.
4. Enter the sketcher workbench.
5. Draw a circle to define the base of the cylinder. Use the sketch tools at the bottom of the screen.
6. Specify the circle's dimensions. In this example, H is 7.723 mm and R is 14.991 mm.

You give the cylinder its height in a later step.

Add a second part

1. Exit the current part workbench to return to the assembly workbench. The toolbars and available tools change when you switch workbenches.
2. Select Insert > New Part.
3. Confirm that the new part (for example, Part2) appears in the product tree under Product1.
4. When the "New Part: Origin Point" dialog appears, click Yes to define a new origin point for the new part.

Sketch the second cylinder

1. Enter the part workbench for Part2.
2. Begin a new sketch on the plane you want, for example the xy plane.
3. Draw a circle to define the base of the second cylinder.
4. Specify the circle's dimensions, then complete the sketch and exit the sketcher.

The source gives two example sets of values:

• Center at H: 1.419 mm, V: 0 mm, Radius: 0 mm initially, then adjusted as needed.
• Circle at H: 34.203 mm, V: 42.576 mm, R: 54.613 mm.

Pad the second cylinder

1. Use the Pad tool to extrude the circle into a cylinder.
2. In the Pad Definition dialog, set the length (height) of the cylinder. In this example, Length is 20 mm.
3. Make sure the correct profile is selected (for example, Sketch.1).
4. Click OK to create the pad.

Review the assembly

Rotate and inspect the assembly to confirm that both cylinders (Part1 and Part2) are present and correctly positioned. The product tree now shows both parts, each with its own body and planes.

Open the Measure Inertia tool

1. Locate the Measure Inertia tool in the Measure toolbar.
2. Click the Measure Inertia icon, a blue cube with a yellow arrow.
3. Get ready to select the part or assembly whose center of gravity and mass you want to find.

Find the center of gravity and mass of the assembly

You can use this technique on any part, sub-assembly, or entire assembly. The Measure Inertia tool offers both 2D and 3D inertia calculations. This guide uses the 3D option.

• To measure a single part, click that part (for example, Part1 or Part2) in the product tree.
• To measure the entire assembly, click the top-level product node (for example, Product1). This analyzes the combined properties of all included parts.

To measure the assembly:

1. With the Measure Inertia dialog open, make sure Measure Inertia 3D is selected.
2. Click Product1 in the product tree.
3. Look at the 3D view. A bounding box appears around the assembly, and a cross marks the calculated center of gravity.

Read the results

The Measure Inertia dialog displays these results for the assembly:

• Center of gravity (G): Gx = 0 mm, Gy = 0 mm, Gz = 97.285 mm
• Mass: 0.262 kg
• Density: 1000 kg/m³ (the default value used for the calculation)
• Volume: 2.615e-004 m³
• Area: 0.039 m²

The dialog also shows the inertia matrix and principal moments for advanced analysis.

The cross in the 3D view marks the exact location of the center of gravity. The coordinates (0, 0, 97.285) give that position in the assembly's coordinate system. The mass is calculated from the default density and the combined volume of the parts. You can use these results for further engineering analysis, design validation, or documentation.