Using Curved Surfaces as a Draft Hinge

It is permitted to use a quilt (curved or flat) as a draft hinge but there are limitations in the context of the draft feature when selecting a quilt for use as a hinge. It appears that you have a spherical surface that you want to use as the draft hinge. Creo has limitations on some axisymmetric geometry due the fact that all circles are split in half. I suspect that is an issue with the quilt you want to use in this case. If you were to extrude the same radius it will likely be usable as a draft hinge but when revolved, it will probably not work.

In your example the method I would use to create the draft feature would be to explicitly select the intersection of the drafted surfaces with the hinge surface (quilt). I think you will find for this geometry that this will be a much more robust approach. Note the use of intent references in the draft feature which will make pattern instances more robust with model edits.

Creo 7 model enclosed for reference.