hi @Gijs i test this command in c# but my Rhino no answer and freeze and my Rhino crash;
is this a bug?
or same doubleNumber must be change?
List<Brep> a=new List<Brep>();
List<Brep> b=new List<Brep>();
List<Brep> c=new List<Brep>();
double[] d;
x.Faces[0].FilletSurfaceToRail(curve,y.Faces[0],.5,.5,3,3,new List<double>(){ 0.0, 0.0 },1,true,FilletSurfaceSplitType.Trim,0.01,a, b , c,out d);
A=a;
B=b;
C=c;
https://developer.rhino3d.com/api/rhinocommon/rhino.geometry.brepface/filletsurfacetorail
fillet rail.gh (9.5 KB)