I assume that u wanna define a 3D rail path using the section you define in the second photo. well, u can define the geometry of the path in any CAD software and save it using xt format. Then import it in ansys Apdl to run the mesh but be aware that due to the complexity of the problem, the mesh will be a bit tricky. but to be honest the mesh will be your last concern, the real concern is the computational time.

Dear sir Kouider Bendine , really Thank you for always being supporting me. I tried to follow this procedure in doing this but the problem i have is in adapting the 3D solid rail according to that path. I tied to do it by defining at the first stage a simple rectangular cross section and then extrude it along the path by using the sweep option in design modeler and in autocad but it doesn't work. i tried to do it also in Design modeler but also it doesn't work. I really don't know how can i do this in CAD environnement. Thank you so much again for all the support.

Sincerly,

Well I am not an AutoCAD User I usually use SOLIDWORKS or Catia and in both it is easy to do so u need the section and the path then sweep the section along the path

Thank you so much dear sir Kouider Bendine. Yes that's the case in AutoCad and Ansys Designmodeler also this is the procedure but it doesn't work for me in this path but I will inchaallah try to do it in Catia or Solidworks. Really thank you so much.

Good luck but u really need to think again about the computing time

Yes that's right dear Kouider Bendine