3D Bezier Curves with wrong surface-normals...and no way to fix it.

I think I found a bug in 2.65:

I defined a 3D Bezier Curve.
The bevel object is a simple circle.
Its basically just a cylinder, bent by ca. 180 degrees.

When I convert it to a mesh (to be able to perform boolean operations with it), the cap ends do not show correct normals. On the one end the normals are showing correctly outside. But on the other end they are showing INSIDE. And it can’t be changed by “recalculate outside”.

Its a serious problem for me, because I have 300 of them in a complex geometry, and I think this is the reason I cannot perform a certain boolean operation.

Is there any creative way I could still correct the normals? The normal official ways do not work.

This is with the latest Blender: 2.65
Sample .blend attached.

Attachments

bezier curve problem1.blend (476 KB)

Remove doubles and then recalculate normals

Thank you Richard! That helped a lot.