Inertia
2D/3D

• Inertia is an option for Body that specifies the centroidal rotational inertia of a body.
• The polar moment of inertia is specified by a scalar in Modeler2D.
• In Modeler3D, the inertia is given as a list of six expressions corresponding to {Ixx, Iyy, Izz, Ixy, Iyz, Izx} for the body. The inertia matrix is then of the form {{Ixx, Ixy, Izx}, {Ixy, Iyy, Iyz}, {Izx, Iyz, Izz}}. Inertia can also be given as the full inertia matrix.
• Inertia[bnum] returns the inertia (2D) or inertia properties (3D) of body bnum.

• The inertia of each body is initially zero, unless otherwise specified.
• The default setting Inertia->Automatic leaves the current inertia properties unchanged.
• In Modeler3D, Inertia is also an option for GyroMoment.
• See also: Centroid, InertiaMatrix, Mass, SetBodies.

Further Examples

Load the Modeler3D package and define a simple model.

In[1]:=

Here are the local inertia properties of the link body.

In[2]:=

Out[2]=

Here the link body is given inertia properties with nonzero products of inertia.

In[3]:=

Out[4]=

See HelpModel3D.