Lofting a straight line does not remain straight
Although I find the results not entirely satisfactory, I'd use a sweep to create side rails and then use surface lofts to create this shape.
@Corvin.Huber wrote:
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Who at SolidWorks would one need to talk to in order to understand this phenomenon?
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Fusion is a product of Autodesk.
SolidWorks is a product of Dassault Systems.
You are on the Fusion forum 😉
The explanation is easy. You need side rails to control the edge flow of the loft.
@Corvin.Huber wrote:
Understand your explanation (side rails) but still am intrigued what the program "is thinking". I am pretty sure it has something to do with cross-section area distribution along the length of the rail.
The program creates a loft according to the constraints you give it. If you don't constrain the loft to follow specific edges it won't. It will create its own arbitrary edge.
The last file is different from the first model. I would stay away from conic curves!
I would create the strut profile and Outside contour sketches first.
Then I would extrude (not sweep, I don't know what I was thinking) the Strut profile symmetrically to Bracket_Width.
Then I would create the loft profile sketches.
Intersect-projecting the strut profile and the outside contour into each profile sketch will create a line where the strut profile pierces through the sketch plane and a point where the outside contour pierces through the sketch plane.
Then constrain the profile splines trough those points.
Now you can loft with predictable results.
Another tip is to avoid offsetting spline curves. It won't have much of an effect in this design, but an have detrimental effect in other designs.
You can see the "artifacts" in the curvature of the offset spline:
Those aren't present in the original spline.
