thank you all for your time! i managed to generate a cycloid with CCycloid 3.4.3 (http://www.cgl.uwaterloo.ca/~smann/ccycloid/) and then imported the *.dxf file into archicad; still had to use the spline though. jean-luc regnier, thank you for the co...

hi! (i'm not sure if i understood «include gravity».) i need to create a roof wich form is generated by a cycloid; the only way i see to do this is by creating a complex profile with the cycloid, and then the roof. thank you!