How can I change the color of the black background?
You can change the background color as well as others in the Display Properties dialog box. For this, click menu "Options" -> "Display Properties" -> "Edit". You can select any background color under "Colors" -> "Other" -> "Background".
Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements
The structural engineering software for design of frame, beam and truss structures, performing linear and nonlinear calculations of internal forces, deformations, and support reactions