Section Properties

You can evaluate section properties for multiple faces and sketches that lie in parallel planes.

You can evaluate different entities without closing the Section Properties dialog box. Clear the selections, then select the entity, and click Recalculate.

When you evaluate more than one entity, the first selected face defines the plane for section property calculation.

Displaying Section Properties for Multiple Entities

To display section properties for multiple entities:

  1. Select any of the following that lie in parallel planes:
    • one or more planar model faces
    • a face on a section plane
    • the crosshatch section face in a section view of a drawing
    • a sketch (click the sketch in the FeatureManager design tree or right-click the feature and select Edit Sketch)
  2. Click Section Properties (Tools toolbar) or Tools > Evaluate > Section Properties.
    The results are displayed in the Section Properties dialog box.
Examine the case of a cylindrical axle with a through all cylindrical cut that creates an open cross-section.

Moment of inertia is calculated as the integration of finite mass elements and their distance to the rotational axis. A section plane has no thickness, so no mass. However, the calculation is possible as an integration of finite area elements.

The complete disk section has Lxx equal to Lyy as expected for a system with rotational symmetry in the Z-axis. Lzz is highest as there is significantly more area away from the rotational axis.

The split section through the cylindrical cut shows a higher Lyy than Lxx as expected, because the remaining area is furthest from the axis rotating about the Y-axis. This difference confirms that the calculation considers the cut.

The rotational center remains in the center of the sections – outside both contours – demonstrating that both regions are included in the inertia calculation.

Open geometry has no area so it cannot give inertia properties.