Hi Rudy, here is an idea on a different approach.
I started with this profile and 2 rails:
Then doing a sweep, turning off the "Maintain height" option:
To tweak the shape you can run another curve down the middle like this:
When you are inside of sweep, you can push the "Pick scaling rail" button and then pick that middle rail curve to customize the shape some more:
So at this point note that the shape is pretty blocky and ends in a flat piece - I have not yet made any attempt to make that part rounded, because trying to force that now would cause a rather sudden change in direction right in that area which will tend to create various kinds of surface flaws, like parts bunched up and running over top of themselves.
At this point you will probably want to delete or hide the curves used for sweeping so they won't get in the way.
Now to make the front part rounded, select the upper edge and do a pretty large fillet:
Then I drew a curve in the top view and selected the main shape, and did a boolean difference to cut it with the curve:
Then another fillet to round off that edge, with a smaller radius than the previous fillet:
Now I can select the bottom face and run a Shell with a small distance (in this case 0.05):
I hope this gives you some ideas on a different approach. One problem is that I did not really drop the smaller end to a tiny point - you can do that, but the sheller will probably not like shelling a shape that comes to narrow point like that, it is likely to fail. So if you want to do that instead of using shell you may need to manually construct a smaller inside piece and then use a boolean to cut it away instead of relying on shell to do it automatically.
The good part about this method is that there aren't profiles that have abrupt changes in orientation, like going from a vertical profile to one slammed down flat on the plane in an abrupt 90 degree change of orientation. Those kind of abrupt changes are going to be what will cause bunching and bad quality surfaces.
- Michael
