How to create bend pipe..ㅠㅠㅠ

I want to make a pipe like the picture.
But I’m stuck with a few problems…

  1. I don’t know how to draw this empty space… I don’t know how…

  2. I want to use CSG to draw the shape of the pipe as shown in the picture, but when I run the subtract part, the Babylon stops…

  3. Finally, I want to create a function that embodies bent pipes depending on the angle

Is there anyone like a hero who can help me build my function?(┬┬﹏┬┬)

PlayGround :

I’m not sure I fully understand the issue. Why don’t you just create an updatable tube?