G3037

G3037 FATAL ERROR: G3037 NON-SINGULAR RIGID MASS MATRIX REQUIRED FOR INERTIAL RELIEF
Cause: An inertial relief analysis was attempted (PARAM, INREL, ON or PARAM, INERTIALRELIEF, ON) and a singular rigid body mass matrix was encountered.
Action: Make sure that density is specified for all materials and that the model has a non-zero mass.
Remarks: None.