Hi Pilou - that's not really a proper setup for a scaling rail... Probably it is generating a very strange warped and chaotic result with a really large number of points in it.
A scaling rail for a 1-rail sweep is meant to follow more along the direction of the path, and also "cover" it completely - meaning any perpendicular you trace out from the path should intersect the scaling rail instead of shooting off into space. It looks like in your case there the scaling rail does not "cover" the entire path.
Here's some illustrations for how the scaling rail works - if you have a sweep with the scaling rail off to the side, like this:
Then when you apply the scaling rail, the sections will attempt to extend along the perpendicular of the path, until they hit the scaling rail like this:
If there is not any intersection available (which I think is the case in some areas in your example), then the original sweep is used for that profile instead, but that will tend to be a very sudden violent change in shape in the surface and will make for some bad results.
Also in your case it looks like the scaling rail is not in the same plane as the path curve, for the most predictable results I would recommend putting the scaling rail in the same plane as the path curve for a 1-rail sweep.
If the scaling rail is not set up in a good relation to the original path curve, you can get a really messy and chaotic result, usually when things take a long time it means that is what is happening - you've got some strange surface result that has a whole bunch of swoops and bulges in it which tends to take a long time to generate during the refinement process and also can take a long time to generate a display mesh for.
So anyway, I hope the illustration above will show you more how a scaling rail is intended to be shaped!
- Michael
|