The two end frames of the cylinder have the same orientation. The translation vectors $L\mathrm{e\_\_axis}$ and $\frac{L}{2}\mathrm{e\_\_axis}$ w.r.t. frame_a define the frame_b and the center of mass frame, respectively.
Cylinder mass is calculated as
$m\=\mathrm{\rho}\mathrm{\pi}\cdot \left({R}^{2}-{\mathrm{R\_\_i}}^{2}\right)L$
where the cylinder material density, ρ, can be defined using the "Select density" parameter. This parameter lets the user either enter a value or select among predefined material densities.
Figure 1: Different options for the "Select density" property
Assuming the default direction of $\left[1\,0\,0\right]$ for the cylinder axis, the moments of inertia expressed from the center of mass frame are
$\mathrm{I\_\_xx}\=\frac{1}{2}m\cdot \left({R}^{2}plus;{\mathrm{R\_\_i}}^{2}\right)$
$\mathrm{I\_\_yy}\=\frac{1}{12}m\cdot \left(3\left({R}^{2}plus;{\mathrm{R\_\_i}}^{2}\right)plus;{L}^{2}\right)$
$\mathrm{I\_\_zz}\=\mathrm{I\_\_yy}$
The right-hand side of these equations will interchange if another axial unit vector is specified.