Software Technology: Fence

For the fence, I started in Soft Image. I modeled each piece individually in Soft Image, and then brought the pieces into Houdini. I had not run into any real issues until I tired to merge everything together at the end. For some reason, when I merged the objects, it acted as if the normals were flipped. I believe that this has something to do with the models themselves, not the process in Houdini, but I'm not entirely sure how to fix it.