Thank you for this excellent spline pipe system, with PBR capability in the material configuration.
With respect to the problem:
You have attempted to increase the pipe size and thickness in the pipe that I PM to your message box? I just did not put here in the post, the link for download, since this is your project.
The left side is your system, the right side is another pipe system that I have changed, which I intend to use as a procedural cave system. As you can see the splines in your system are broken, they are straight, after collision activated and pipe size increased for the player’s height, to be able to walk inside
I realized that I can use the scale tool to reduce the control points for each pipe’s spline node. And this seems to have solved the problem, but the interpolation lines in between the nodes are straight, the same thing does not happen with other system and if I add a new node between two spline points (nodes), in between two pipe sections happens a terrible overlap. If this is not very clear, I can PM to you the modified pipe’s blueprint file again.