So i have a curvy object that i want to act as an obstacle for water, but i have not idea how to get it to work, what settings do i use?
Enable Fluid > Enable Obstacle
but the water does not fall down my half pipe shaped thing.
Ok, in that case, I think I need to refer you to one of the fluid tutorials. It is clear one of your settings is incorrect. http://www.blendernation.com/2006/01/21/fluid-simulation-in-blender/
You could also upload a blender file and I can take a look at it for you.
check your normals