Using the following code I've generated an stl, but if I import it along with
another stl, it displays with F5, but doesn't with F6. If I comment out the
mirror([0,0,m]) line, it displays in both. I'm using 2015.03

translate([-1.25,-25.375,0])
cube([5,11,89],center=true);

for(m=[0,1])
{
mirror([0,0,m])
{
translate([0.75,-30.75,14])
{
linear_extrude(height=4, center=true)
polygon(points= [
[0,0],
[0,48],
[0.5,48],
[3.5,47.5],
[4.5,28],
[4.5,0]
]);
}
}
}

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I could not see anything wrong or inappropriate with your code (although I
would never use mirror([0,0,0])). It seems to be a bug in the stl
generation. I could generate a corrected stl by unifying duplicated vertices
with Meshlab.

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That doesn't seem to work for me, though I'm not very experienced with meshlab.  I've played about with the issue.

1. issue exists if mirror is replaced by translate

2. issue goes away if the intersecting cube is split into 2 separate cubes - as long as they don't touch or overlap.

From: Discuss discuss-bounces@lists.openscad.org on behalf of Ronaldo rcmpersiano@gmail.com
Sent: 30 October 2016 14:01:07
To: discuss@lists.openscad.org
Subject: Re: [OpenSCAD] Mirror, linear_extrude and importing an stl

I could not see anything wrong or inappropriate with your code (although I
would never use mirror([0,0,0])). It seems to be a bug in the stl
generation. I could generate a corrected stl by unifying duplicated vertices
with Meshlab.

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View this message in context: http://forum.openscad.org/Mirror-linear-extrude-and-importing-an-stl-tp18825p18828.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

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