Polygons with holes??

[David Etlinger]

I'm guessing you can't do this directly, but are there any tricks? In
this example I'm trying to draw a loudspeaker. The tweeter/woofer
cones go back into the body, but I need a front face to cover the rear
edges. The closest I came was using lay=over, but of course that is a
hack and only works when viewing the front.

Thanks as always for any help!
David

def speaker {
def w 1 %width, x-axis
def d 1.5 %depth, y-axis
def h 2 %height, z-axis

def thefill [fill=lightgray]

%front vertices
def f1 (0,0,h) def f2 (w,0,h)
def f3 (0,0,0) def f4 (w,0,0)

def r1 (0,d,h) def r2 (w,d,h)
def r3 (0,d,0) def r4 (w,d,0)

def front polygon[thefill] (f2) (f1) (f3) (f4)
def back polygon[thefill] (r2) (r1) (r3) (r4)
def left polygon[thefill] (f1) (r1) (r3) (f3)
def right polygon[thefill] (f2) (f4) (r4) (r2)
def top polygon[thefill] (f1) (f2) (r2) (r1)
def bottom polygon[thefill] (f3) (r3) (r4) (f4)

def n 16
def woofer_center (w/2, 0-ee, h/4)
def woofer_radius h/5
def woofer_pt ( (woofer_center)'x, (woofer_center)'y,
(woofer_center)'z + woofer_radius ) %HAS to be a better way
def woofer_inner_pt ( (woofer_center)'x, (woofer_center)'y + d/5,
(woofer_center)'z + 0.5*woofer_radius )
def woofer sweep[lay=over,fill=gray]{ n<>, rotate(360/n,
(woofer_center), [ay]) } line (woofer_pt) (woofer_inner_pt)

def tweeter_center (w/2, 0-ee, (3/4)*h)
def tweeter_radius h/7
def tweeter_pt ( (tweeter_center)'x, (tweeter_center)'y,
(tweeter_center)'z + tweeter_radius )
def tweeter_inner_pt ( (tweeter_center)'x, (tweeter_center)'y + d/5,
(tweeter_center)'z + 0.5*tweeter_radius )
def tweeter sweep[lay=over,fill=gray]{ n<>, rotate(360/n,
(tweeter_center), [ay]) } line (tweeter_pt) (tweeter_inner_pt)

%center at the origin
put {translate([-w/2, -d/2, -h/2])} {{front}{back}{left}{right}{top}
{bottom}{woofer}{tweeter}}
}

[Gene]

Sorry. Since all polygons must be convex in this version, your only
recourse is to divide into several polygons that are all convex.
Unfortunately because edges are all or nothing, you will have
(probably unwanted) rules at the divisions. E.g. note the palm of the
hand in the manual has an extra rule where its concavity was divided.
Version 2 will divide non-convex polygons automatically into a
delaunay triangulation.

Your hack is a reasonable albeit fragile work-around.

Gene

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