Abstract
This article discusses the design, calculation and analysis of the stress-strain state of a steel rafter truss using the LIRA-CAD computational and analytical software package; applications: KM-CAD and STK-CAD. he task of implementing the most effective method of selecting rolled profiles for the rods of a hinged-rod structure - a rafter truss, taking into account the requirements, cost-effectiveness, unification and optimal use of the bearing capacity of structural elements, has been completed. The process of using color gradient scales for visual engineering analysis of a constructive system is also considered.