Get mass properties for a row in a data frame

get_mass_props() creates a mass properties list from a selected row in a data frame.

Usage

get_mass_props(df, id)

Arguments

df

A data frame with (at least) these columns: id, mass, Cx, Cy, Cz, Ixx, Iyy, Izz, Ixy, Ixz, Iyz, POIconv, Ipoint.

id

The id value of the desired row.

Value

A list with the following named elements:

• mass Numeric mass.

• center_mass Numeric 3-vector center of mass.

• point Logical indicating point mass. The inertia of point masses is excluded from calculations.

• inertia Numeric 3x3 matrix inertia tensor. The signs of the off-diagonal elements of the inertia tensor are determined by POIconv. For example, the \(xy\) element of the inertia tensor is Ixy if POIconv is "-"; it is -Ixy if POIconv is "+".

Examples

get_mass_props(mp_table, "C.1.2.2.3.1.2.3")
#> $mass
#> [1] 0.1213345
#> 
#> $center_mass
#>        x        y        z 
#> 70.54848 81.54389 44.52262 
#> 
#> $inertia
#>              x             y            z
#> x  0.143256682 -0.0123144484 0.0012773920
#> y -0.012314448  0.1458692409 0.0003485651
#> z  0.001277392  0.0003485651 0.1309228273
#> 
#> $point
#> [1] FALSE
#>