$\newcommand{\Dev}{\operatorname{Dev}}$ $\newcommand{\dev}{\operatorname{dev}}$ $\newcommand{\grad}{\operatorname{grad}}$ $\newcommand{\divg}{\operatorname{div}}$ $\newcommand{\Ei}{\operatorname{Ei}}$ $\newcommand{\tr}{\operatorname{tr}}$

This constant body force per mass $\mathbf{b}$ is defined as a 3D vector. Each component can be associated with a load curve to define a time dependent body force. Only the non-zero components need to be defined. This type of body force is spatially homogeneous, though it may vary with time when associated with a load curve:

<body_load type="const">
  <x lc="1">1.0</x>
  <y lc="2">1.0</y>
  <z lc="3">1.0</z>
</body_load>

The lc attribute defines the load curve to use for the corresponding component. The values of the components can be used to define scale factors for the load values.