You can add a Center of Mass (COM) point to an assembly. COM points added in component files also appear in the assembly.
The position of the COM point updates when the model's center of mass
changes. For example, the position of the COM point updates as you add, modify, delete,
or suppress components or add or delete assembly features. The COM point can be useful
when you are designing assemblies requiring balanced mass (for example, to avoid
excessive vibration).
In an active assembly, operations for the center of mass and equations
linked to mass properties are updated only when they take 0.5 seconds or less. If the
update takes more than 0.5 seconds, the center of mass and equations are marked with
, and are not updated until you
rebuild
manually.
The calculation of the center of mass includes:
- Hidden components
- Lightweight components. However, COM and COMR points created in
the component files of lightweight components are not visible in the parent
assembly.
To exclude a component from the calculation
of
the center of mass, make it an envelope
component.
If
the COM point does not update after creating an envelope component, press
Ctrl + Q to update the position of
the COM point.
You can mate to the COM points of an assembly’s components in distance,
coincident, and concentric mates. You cannot mate to the COM point of the assembly
itself.
If you add COM points or Center of Mass Reference (COMR) points
in
the component files, the points appear in the parent assembly:
 |
Center
of Mass, part |
Indicates the center of mass of a
component that is a part. Defined in the part document. |
 |
Center
of Mass, subassembly |
Indicates the center of mass of a
component that is a subassembly. Defined in the subassembly
document. |
 |
Center
of Mass, part, user-defined |
In an assembly, indicates a
user-defined center of mass of a component that is a part. Defined
in the part document, in the Override Mass
Properties dialog box. |
 |
Center
of Mass, subassembly, user-defined |
In an assembly, indicates a
user-defined center of mass of a component that is a subassembly.
Defined in the subassembly document, in the Override Mass Properties dialog
box. |
 |
Center
of Mass Reference Point |
Indicates the center of mass of
the features above the point in the FeatureManager design tree of
the part. |
For example, in this assembly, 
indicates the center of mass of the
assembly, and indicates the centers of mass of three component
parts:
If the COM and COMR points are not visible, click
View Center of Mass
(View
toolbar) or .