Andrei,

>>Green Cylinder is perefect one, and it stay behinde his cylinder. As you can see his cylinder is wrong, it is becouse he made that spiral detail constant radius.
To avoid that artifacts that his model has, cylinder must be perfect...
This model have 2 mistakes it has artifacts and it is not perfect cylinder. Also it had messy geometry.
Do not know may be this things are not important for molding <<

I know you are trying to help but you don't understand the design intent. A perfect cylinder will not work here as it will change the geometry required for the article. THIS IS NOT NEGOTIABLE. I appreciate your input but it isn't helpful in this case.

Hello,

With some helix formula help from Michael I am trying to recreate the part using a variety of techniques using MoI only (I'm using Rhino/VSR for curvature, deviation and light lines analysis). There's more than one way to do this but my objective in the exercise is to have a controllable and flexible set of surfaces. The interior details should be an interesting challenge.