Hello!

on the path to more complexity i hit another wall:

in roundPoint i can't add the test? it gives me a syntax error in  front of
the for loop?

and the main problem, i can't feed this to a polygon, each function adds a
nesting to the produced array, how do i avoid this?

my son had the ... delightful.... idea of drawing a dragon, so i started on
something to build the beak of it... i begun to draw the rough shape , and
once having that shape i wanted to smooth it out, but it didn't work as i
supposed it would...

thanks for any help!
Bruno

echo("poly",  kieferPoly(b  =40,l = 70,lw=10, d=2)) ;

function baseForm(x, b, l) = (b!= 0)? 4l/(bb) xx - l:0;
function curveAngle(l, y0, ueber, lw,hprim) =  (l+y0 <= ueber)? 105-2*lw -
atan((ueber -y0)/hprim):(y0 == 0)? 0:-atan(y0/hprim);

function roundPoint(pt,rad, res = 3,above = true) =
[
//(above == true)?
for(n = [0:1:res])
let (w = 180 + 180/resn)
[pt[0]+radcos(w),pt[1], pt[2]+radsin(w)]
// :
//        for(n = [0:1:res])
//            let (w = 180/resn)
//              [pt[0]+radcos(w),pt[1], pt[2]+radsin(w)]
];

function transvCut(x,y,z,d=1,res=3) =
[
roundPoint([x,y,z],d,res),
roundPoint([0,y,z+x],d,res, above = 0),
roundPoint([-x,y,z],d,res)
];

function kieferPoly(b,l,lw=10, d=2) =
let(curve = sqrt(ll+ bb/4))
let(hprim = curvecos(lw))
let(  ueber = curvesin(lw))
[
for(x = [-b/2: 1 : 0])
let(y0 = baseForm(x,b,l))
let(beta = curveAngle(l, y0, ueber, lw,hprim))
transvCut(x,y0,curve*cos(beta)-hprim,d),
];

--
ciao
Bruno

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Yes, the list comprehension is not a general expression.
I'm not sure it's possible to change that.

Both branches look the same anyway, so I'd use

w = 180/res*n + above ? 180 : 0

As for nesting, check this post:
http://forum.openscad.org/2D-SVG-concat-points-point-no-output-loops-amp-conditionals-vector-declarations-td29068.html#a29070

You can drop one nesting level using 'each'

For some extra ideas for drawing using math, check
out https://www.desmos.com/art

ciao,
Torsten.