Hi
Use step as solid part.
In the option of step you can choose ver: 203 / 214.
Ask the ProE user if he can read step and whick version.
If he can't read step ask him on sat.
If he can't read step it's a problem. try iges like solid, and if not as surfaces. He will have problems with it.
If that...
Inventor 6 have new option call "Grounded work point" which help defining the points of the pipes.
Inventor 7.5 that will be released in the summer, there will be an option to buy special application for piping build by autodesk.
You need to build tangent work plane to the cylinder.
Enter work plane command and press right mouse button on the screen. A visual help will appear and you can pick wich film to see about creating work planes.
After creating it, Crete a new sketch on it ang project the circular sketch for...