Thanks, Don. That's always good to hear. There's more than a bit of blood and sweat in the doing and learning. In mentioning how it was done I meant to communicate that the design is worked out (essentially by a 19th century system based on cylindric sections) before the rail is actually made. Although I have a couple production methods I'd love to incorporate to further improve my efficiency, it's getting to look like 'John Henry and the Steam Drill' business-wise. I recently found out the cost that that particular rail was quoted on by a shop with 5-axis CNC. As attached as am to the antique technology I've had my head in for so long, I've got to move forward. More free time away from the shop is not an entirely bad idea.
I've been spending time going over the 2-D environment of Platinum, and it seems close enough to the ancient version of 2D A-cad that I've been using that I'm satisfied and encouraged. All of the above may be too much information, but it would be lovely if it inspires a Turbocad ace to engage.
Anyway, I've been looking over the 3-D tools. What I've run into with 3-D programs (I'm quite proficient with SketchUp) is that when a profile is extruded along a spiral, or inclined circular path (wreathed in "stairbuilder-ese") it twists. I believe there is a setting or parameter which is set in A-cad which controls that twisting even as it maintains the face of the extruded(swept, drawn, etc.) profile essentially square to that path. If this is so, I'm hoping that same control is available in Turbocad Platinum.
Another thought ------ If I were to define a proper path for such a rail via NURBS, and then place 2-D objects correctly oriented at necessary locations along that path, could the rail be developed using a version of the loft tool? If this were to work would it be accurate enough for export to CAM or only a rough or distorted approximation?