Simple Sweep1 generating bad objects and weird surfaces

Hello, I’m trying to just create a simple gothic arch here with a triangular profile. My idea was just to create a guiderail with as few control points as possible and then do a simple _sweep1 with my triangle as you can see. But when i do, the resulting polysurface comes out weird and asymmetrical, with some surfaces joined and other ones not.

Here’s my guiderail. As you can see there’s no unnecessary control points. It’s just a simple shape with a few curves and corners. My triangle is also just a simple polygon.

My result however is really strange. It’s asymmetrical and has generated more surfaces than necessary on one side only?? Additionally, my result is somehow a “bad object” and gets selected after i run _selbadobjects

Why would it do this? In my mind this is just supposed to be a simple sweep. Just a simple extrusion along the rail. The split surfaces makes it bad for _make2d since it generates extra lines.

Repositioning the triangle does nothing to fix my problem. Aligning the cross-sections differently also does nothing.

What’s going on here? I’m on latest version for Mac. Any help would be greatly appreciated.

I have tried _shrinktrimmedsrf but it did nothing. I also tried exploding my shape and rebuilding all individual surfaces, but it didn’t fix the “bad object” status, and additionally I couldn’t use the resulting “rebuilt” polysurface for any booleans which was really weird.

Thanks for listening

Please post the file with the curve and the profile…

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