Is it possible to convert a truss attic into living space?
Converting roof trusses to rafters
How to Modify Wood and Attic Trusses
Can a Common Truss Be Converted Into an Attic Truss?
How to Replace Roof Trusses With Stick Framing
How Feasible Is It to Remodel Your Attic?
A Loft Conversion.

Bottom line: it can be done, get a structural engineer.

Definitions:

roof truss

A structure to hold up the roof that includes diagonal members to provide support. These are usually (always?) manufactured offsite, rather that fabricated on site.

attic truss

similar to a roof truss, but has a rectangular space in the center of the truss to provide usable space.

rafters

beams that support the roof, with no internal bracing.