In which software can we design and analyse custom structures? For example a sign on roads? Unipoles? Billboards? Please help.

I do agree that Sap2000 can model any structure using finite element method   but we (as engineers) should check the resultant mathematical model and examine the way the program use when handling intersection nodes . a few simplifications can be accepted accepted, however some patterns are difficult to model all together so we should do the calculations of  some of these members separately and avoid excessive modeling.

when talking about non-uniform structures in regions subjected to strong wind  (honestly I don't face such a problem) then we can use autodesk Robot program that has the ability to simulate wind flow around the structure.

we can design and analyses roads pole, unipoles, & billboards using these software. first 2 nos spcific for pole design & analyses others also we can design but that not for pole design as like.

1- GUYMAST (GUYMASTER)

2-PLS POLE

3-SAP2000

4-STAAD PRO

we can calculation every member using this software.

i think sap200 would be the one