Assembly mass properties


Use the BMMASSPROP command.

An assembly can consist of multiple parts made from different materials. To correctly compute the mass, center of gravity (centroid), and inertia of such assemblies, BricsCAD® supports individual densities for components.

A physical material for a mechanical component is defined in the Material property in the Mechanical Browser.

By default, a component inherits the density of the assembly, into which it was inserted, or formed from.

Set the mass units

  1. Open the Settings dialog box.
  2. Expand the Property units settings under Drawing / Drafting / Drawing units.
  3. Tick the Format mass properties checkbox to enable formatting of mass values with appropriate units.
  4. Select the Mass units field.
  5. Click the Browse button .
  6. Specify the desired mass units in the MASSUNITS dialog box.
    Note: The Mass units setting affects the mass values only. Other mass properties such as density or moments of inertia will be formatted in SI units for the metric system and in imperial units for the imperial system, regardless of the value of the Mass units setting.
  7. Specify the desired precision in the Mass precision field.
  8. Close the Settings dialog box.

Compute the mass properties

Use the BMMASSPROP command.

You can compute mass properties for the entire model or for a selection of 3D solids and/or subcomponents. The values of mass, volume, centroid, moments of inertia, products of inertia, radii of gyration, principal moments, and X-Y-Z directions about centroid are reported in the Command line.

Optionally, you can align the User Coordinate System with the inertia axes. As a result, the center of mass or centroid of the component lies at the origin of UCS, which can be useful to investigate the behavior of a product under gravity force.