Please explain Regeneration Failure

I would like to understand why these two forms are either possible or not possible to create using a complex surface using the Form Create function. I have attached three files - one is a process diagram I step by step explain how I had to go through several steps to get the form to work, but it is not the same as the form that I wanted to make (the Example 01 image on the right). How is it that the form looks like it would work, but does not and forces me to make the image on the right (Example 02). Both example files are included as well. Please explain.

Hi Brok,

Sorry for radio silence, we have people on vacation this week and others heads down on new stuff.

If I understand the viseo diagram and the example 1, you want to take a saddle-shaped ruled surface and extrudes it vertically, correct? so the issue is the Make Form command is guessing which way to extrude and is going sideways, not up, right? this is because it is using the normal at the middle of the surface i believe.

here is another way to get what you want:

- rather than using points and making a ruled surface, start from a extruded box.

- select a side, vertical edge.

- drag it up via the vertical edge manipulator

- you now have two ruled surfaces (top and bottom) that are still connected with vertical edges, all of the same length.

- you can move another edge up to make the saddle shape more apparent.