No, you cannot add new profiles to Trussmaker. You would have to build your truss manually with your profile - for example, using the beam tool and the truss flat on the ground. View the finished truss in 3D from the side (so that the top of the truss is what you are looking at) and then save as a GDL object - which will save that orientation for subsequent placement. Keep the on-the-ground truss around for subsequent modifications.
If you change your profile or the truss, you will have to re-save the GDL side view version. (If you create a saved view of the truss, the re-save is quick and easy as you don't have to concern yourself with getting the orientation right again.)
You can purchase add-ons such as Objective which simplify the process and let you build and rotate visually and subsequently edit the profile, and trim the truss as required for peculiar locations in your building.
Cheers,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB