Ansys Employee
"How to set elements for modal analysis" - Do you mean how to select a few parts as rigid while rest as flexible? You could do it the same way you as you did in static structural by changing the part behavior. Please let me know if I couldn't interpret your question correctly. Regarding the second question, why did you use a point mass approach instead of a specifying a suitable density value density to the material? Is this because you don't know the density? You could click on the required part with a body select tool and the parts volume would be displayed in the lower right corner, you could divide the mass by this value to get the density and change it in engineering data.
Regards Ishan.