Has anyone found the advanced dynamic random studies in mechanica to provide useful results? I have read PTC's website and other sites related to advanced random studies, the information is limited and not in a scope with real world applications with respect to mechanica discussing solutions, I have talked with PTC customer support, they have not been helpful as usual. I need to solve a problem that requires advanced random approach to ensure that a mechanical assembly is structurally sound. Background: I have an input ASD (g^2/Hz) curve that I have used in conjunction with a base excitation loading scheme and accounted in xyz for gravity (386.4) scalar to excite the assembly. I have looked at the modal analysis to ensure convergence (16 natural freq's). I have created measures on a point where I believe one will see the most displacement (xyz) during the random qualification. Since mechanica is working in the RMS realm, it seems that the results may be subjected to error that is all negative numbers result in positive ones? Integrated mode using WF 2.0 I can not get von Mises stress results over the model (in the past, I was able to use pro2001 and get a fringe plot of von Mises over the models)? Results related to the displacements are in the x, y and z directions, do these max displacements need to be combined into a resultant form. I gather that mechanica is dealing in a probability solution? Is the approach similar to Miles eqns? Anyone that has used mechanica to solve a real world random analysis on a project, please discuss the results scheme of mechanica in some detail with me, your knowledge and guidance would be greatly appreciated.