Using circular path curves for Grasshopper Beam Styles does not work. It is not possible to select the curve. I know the workaround would be to split the circle in two halves, but it is a very impractical thing to do because of the loss of control, time required to do it over and over again for design variations. Would be great if this could be addressed in an upcoming service release.
Thanks - S
Beams can’t be created from circular closed curves (neither in GH), unless you split them into different parts. We will consider supporting this opinion in future versions.