truss command vs pbrace command

I want to discuss about the two options in staad pro,
1) assigning truss specs to members
2) assigning pb brace command in parameters to top and bottom chord.
i want to ask whats the difference between these two? if i use truss command what effect it will have on the truss and whether i have to assign restraints that is pbrace command if i have assigned truss specs to members or not?
pbrace command is use to apply top restraint and bottom same as unt and unb but at specific points.?

i have these two models in which i have used pbrace command and truss command .. the model with truss command is passing the truss but in pbrace command and releases the model is not passing.

TEST .STD2308164-KON .STD