I'm trying to do something that seems conceptually simple to me, but it keeps failing. Rather than passing a parameter-less shape() function into sweep(), I am passing a function with one parameter, the scale. This should allow me to use a circular cross section to create a snake-that-swallowed-a-grapefruit shape, by varying the scale dynamically. In the implementation of sweep() I changed this function, as follows (I calculate to_3d() of the shape() each time):     function sweep_points() = flatten([for (i=[0:pathlen]) transform(path_transforms[i], to_3d(shape(i)))]); I renamed sweep.scad to be sweep-jon.scad.  While sweep-jon.scad compiles without errors, the invocation code (below) fails with"Ignoring unknown function 'shape'" and then "PolySet has degenerate polygons". What am I missing? use <sweep-Jon.scad> function f(a) = [18*sin(360*a), 18-18*cos(360*a*0.7), 36*sin(360*a/2)]; function shape(d) =     [for (i=[1:10:360]) [d*sin(i), d*cos(i)]]; step = 0.005; path = [for (t=[0:step:1-step]) f(t)]; path_transforms = construct_transform_path(path); sweep(shape(), path_transforms); -- Sent from my desktop computer. I do not receive emails while away from my desk, nor do I receive texts on my main phone number (which is a land line). If you know that I am on the road, please text me. If you know that I am home, please email me.

 function sweep_points() = flatten([for (i=[0:pathlen])

You can't pass functions in OpenSCAD. You are simply passing in the result of calling the function with no argument. So inside sweep it has no access to shape(). On 2 January 2018 at 21:15, jon <jon@jonbondy.com> wrote: > I'm trying to do something that seems conceptually simple to me, but it > keeps failing. > > Rather than passing a parameter-less shape() function into sweep(), I am > passing a function with one parameter, the scale. This should allow me to > use a circular cross section to create a snake-that-swallowed-a-grapefruit > shape, by varying the scale dynamically. > > In the implementation of sweep() I changed this function, as follows (I > calculate to_3d() of the shape() each time): > > function sweep_points() = flatten([for (i=[0:pathlen]) > transform(path_transforms[i], to_3d(shape(i)))]); > > I renamed sweep.scad to be sweep-jon.scad. While sweep-jon.scad compiles > without errors, the invocation code (below) fails with"Ignoring unknown > function 'shape'" and then "PolySet has degenerate polygons". > > What am I missing? > > > use <sweep-Jon.scad> > > function f(a) = [18*sin(360*a), 18-18*cos(360*a*0.7), 36*sin(360*a/2)]; > > function shape(d) = > [for (i=[1:10:360]) [d*sin(i), d*cos(i)]]; > > step = 0.005; > path = [for (t=[0:step:1-step]) f(t)]; > path_transforms = construct_transform_path(path); > sweep(shape(), path_transforms); > > -- > Sent from my desktop computer. > I do not receive emails while away from my desk, > nor do I receive texts on my main phone number > (which is a land line). > If you know that I am on the road, please text me. > If you know that I am home, please email me. > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >