buffering PolylineZ into PolygonZ

I have about 1000 polylineZ features that I would like to convert into polygons of a constant width, and the same length as the line. The buffer tool created 2D, not 3D features, and the 3D Buffer tool created multipatch features. When viewed in ArcScene, I would like the features to look like the polylines, only with width, and no thickness. Ideas? Thanks!