Sorry for the delay in getting this uploaded I got side tracked last night.
Here are two videos showing how to use profile curves to make cutting planes to use to cut up a polygon pipe using booleans.
The first video is about 15 minutes and covers the creation of the top section and the second video is only 5 minutes and shows how to create the bottom section for a perfectly fitted completed part.
I dropped the step to split the model in half as it was not necessary.
I hope you find this helpful. Please feel free to ask any questions if anything confuses you.
I am not sure how much bandwidth I have remaining on screencast.com so if I run out and you cannot run the video I will put another copy of both on YouTube.com later today.
Here is what we make:
Here is the link to part 1 - the top section...
https://www.screencast.com/t/YWVjODU5ZDk
Here is the link to part 2 - the bottom section...
https://www.screencast.com/t/NzIxODEyY2
Enjoy! I will post the .obj final file later.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675