Curve Modifier Gives Unexpected Effects I am having problems understating the curve modifier. I can usually get it to do what I want, but only after a lot of trial and error and often I plain do not understand why it seems to work in the way it does.

I attach a blend file. I am trying to make a bridge by having a segment of the bridge, a curve for it to follow and using the array and curve modifiers replicate it along the path. I have applied scale and rotation, and made sure both the bridge segment and the curve share an origin. Still it seems to give bizarre results.

In the attached file, when I turn on the curve modifier, the bridge segment flips on its side. I am completely stumped by this. Why is this happening?

Example Blend File
The tilt of individual (or all) points on a curve can be adjusted by highlighting the relevant control points and pressing Ctrl+T followed by making the adjustment.

When you are using another object with a curve modifier this will adjust the orientation of that object as it follows the curve.