# Analysis Wizard : Explicit Time History Mass & Damping
Explicit time history analysis - mass and damping definition
Mass scale factor on element masses
Element masses will be lumped at the element nodes, this factor can be used to magnify or reduce the element masses used in the analysis.
Mass derived from loads
Case definition: define the load or load combination that is used to derive masses
Direction: specify which direction of the loads to be used in deriving masses
Scale factor: the factor is used to magnify or reduce the masses derived from loads
Damping option
Damper elements: check this box to include damping from damper elements. If there is no damper element in the model, checking this box will make no difference
Rayleigh damping: define Rayleigh damping by specifying two frequencies and corresponding two critical damping ratios. Wizard is available for defining the Rayleigh damping by giving alpha and beta parameters directly.