I have had this problem of not being able to get a coordinate system on an imported helix true to its center. I know how to put a new coordinate system on imported models with corners, and saving them as parasolids. When it comes to imported helix shapes that have the coordinate system not true to the helix, I have struggled to the point of giving up, and not trying (telling the customer to send CAD that has the coordinate system true to the helix). Being that I work for a spring manufacturer, I tend to see a lot of imported helix's. I want to get around having to call the customer to send new CAD (time is money). If there is a way, I would like to know, and I would appreciate any help.
Here is an example of my problem. Notice that it is the front view, but the spring is not true to it.
Again, any help is appreciated.