# [OpenSCAD] vanishing polyhedra on difference?

Bruno Boettcher bboett at gmail.com
Sat Jul 20 11:32:19 EDT 2019

```Hello,

so my previous question was stupid enough :D so i went into looking to
achieve the desired result directly by using the polyhedrons, and here's
the next dumb question:

if you activate the difference on line 36, everything vanishes :(
why?? (same for union BTW....)

l = 3;
dlu = 1.4;
dlo = 2.9;
w= 30;
h= 11.5;
uo = 9;
uxo = 25;
uxu = 27;

module einschubForm(untereBr,obereBr,absend,absanf,abshoehe,hoehe,breite)
{
obVerjBreite = (obereBr-untereBr)*abshoehe/hoehe+untereBr;
polyhedron(
points=[[-untereBr,0,0], [untereBr,0,0], [untereBr,breite,0],
[-untereBr,breite,0], //unteres Rechteck
[-obereBr,0,hoehe],[obereBr,0,hoehe],
[obVerjBreite,breite,abshoehe],[-obVerjBreite,breite,abshoehe]    //oberes
Rechteck
,[-obVerjBreite,absanf,hoehe], [-obVerjBreite,absend, abshoehe],
[obVerjBreite,absend, abshoehe], [obVerjBreite,absanf,hoehe] //Absenkung
,[-untereBr,absanf,0], [-untereBr,absend, 0], [untereBr,absend, 0],
[untereBr,absanf,0]
],

faces=[
[0,3,2,1], //unten
[1,2,6,10,11,5], //hinten
[2,3,7,6], //stirn rechts
[0,4,8,9,7,3], //vorne
[4,5,11,8], [8,11,10,9], [9,10,6,7]  //oben
]
);
}

posx = 11.1;
posy = 0;
posz = 1.71;
translate([posx,posy,posz])
{
//difference()
//{
einschubForm(dlu,dlo,uxu,uxo,uo,h,w);
color("blue") translate([1,1.5,1])scale(v = [1, .9, .8])
einschubForm(dlu,dlo,uxu,uxo,uo,h,w);
//}
}

--
ciao
Bruno

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