I trying to make a rib that follows the edges of the column, but it doesn't work the way I wanted it. How am I supposed to know how much I need to turn the bevel object to get the desired effect? I don't wanna change the location or rotate the curve because it would be later hard to fit it perfectly into the vault. Or maybe there is a different way to do it?
For a Bevel-Object swept along a curve-path, the rules are:
- The Bevel Object will be projected down its own positive Z axis.. its own positive Z is 'Front', as it travels down the path.
- It doesn't matter where the path's object-origin is.
- It doesn't matter where the the Bevel-Object is in the world. Its object-origin will lie on the path, when projected, (assuming no Offset in the path's Data > Extrude panel).
- 'Up', with respect to the path's normals, will be the Bevel-Object's own positive Y axis
- 'Right', looking down the path's direction, will be the Bevel-Object's own positive X axis.
This is quite hard to illustrate clearly. I suggest moving the profile-curve to somewhere it's convenient to work with, maybe the World origin, and switching on the display of the path's normals in its Edit Mode, in the Overlays dropdown.
First check that the path's normals are left-to right, at right-angles to your desired 'Up'. Setting its Twist Method to 'Minimum' in its Data > Shape panel should do that.
Then rotate the profile in Edit mode, so it's flat in XY, and its top is pointing down its own positive Y axis. In the profile's Object > Viewport Display panel, you can switch on 'Axis', as above, to reassure yourself of the alignment.