An update on the previously posted link to the Thingiverse chamfered text
generator.

It accepts font names not listed in the file, as long as they are installed
on your computer.
You can get "mirrored" text required for a stamp by entering a scale number
less than one.
Doing so removes the binding plate from the bottom of the letters and also
spaces out the letters, but you can adjust kerning in the file. For the
binding plate, one simply adds a flat cube at the appropriate location. The
original binding plate should be neutralized by zeroing out that value in
the cod.

I don't have the smarts to analyze the creator's code, but the one negative
that jumps out is that a dot on a period is going to be on a slanted stalk,
a not particularly strong structure in the 3D printed world, but also one
that could be manually modified with some experimentation.

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This script also use SCALE so the result is not what I need. As you can see
in the pictures bellow all walls are outward
http://forum.openscad.org/file/t2613/3.png

I will try Minkowsky

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More like this?

http://forum.openscad.org/file/t1309/russian2.jpg

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Yes, like this.

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I could not figure out how to do it inside OpenSCAD so I did it in AutoCAD.
I traced the letters in AutoCAD and created polylines of the outlines of the
letters.
Then I offset the polylines and moved the offset polylines up (+Z) by 3mm or
whatever letter height I needed.  Many years ago I wrote a routine in
AutoCAD that produces a TIN (Triangulated Irregular Network, similar to a
Delaunay triangulation) which creates 3DFACEs like what you have in an STL
file.  I used this routine to create a TIN of the letter.  I also wrote a
routine that produces an STL file from the TIN.

Are the letters in your DXF file all that you need or do you need an entire
alphabet?
If an entire alphabet, do you have a Truetype font file of the alphabet?
I can create STL files of each letter if that would help you.

The “curved” parts of the letters in your DXF file are made of rather long
line segments that I can also “smooth” if you wish (see attachment).
Send me an email if interested.
Charles

http://forum.openscad.org/file/t1309/russian5.jpg

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I wrote an offset() function that operates on a list of coordinates.  Using
this function you can compute the offset and place the offset points at a
different z, and then use polyhedron to link everything together.    It's
sort of messy, though, because of all the internal holes in text.  And you
have to have your data in OpenSCAD as a list of values, not as geometry.
It runs in 0s, so no time issues.

http://forum.openscad.org/file/t2477/star1.png
http://forum.openscad.org/file/t2477/star2.png

Here's a code example:

include<BOSL2/std.scad>

outside = reverse(star(d=10, id=5, n=7));
inside = offset(outside, delta=-1, closed=true);

shrink_outside = offset(outside, delta=-.4, closed=true, return_faces=true);
grow_inside = offset(inside, delta=0.4, closed=true, return_faces=true);

outside_pts = concat(path3d(outside,0),path3d(shrink_outside[0],1));
inside_pts = concat(path3d(inside,-.01), path3d(grow_inside[0],1.01));

outside_faces = concat(shrink_outside[1],
[reverse(list_range(len(outside)))],
[add_scalar(list_range(len(outside)),len(outside))]);
inside_faces = concat(grow_inside[1], [reverse(list_range(len(outside)))],
[add_scalar(list_range(len(outside)),len(outside))]);

difference(){
polyhedron(points = outside_pts, faces = outside_faces,convexity=10);
polyhedron(points = inside_pts, faces = inside_faces,convexity=10);
}

Hmmm.  With minkowski() it's going to be hard (impossible?) to avoid
rounding over the source geometry.  I took a stab at that, continuing my
example above.

$fn=32;
minkowski(){
linear_extrude(height=.01)
offset(delta=-.4)
difference(){
polygon(outside);
polygon(inside);
}
cylinder(r2=.2,r1=.5, h=1);
}

So that gives rounded edges and takes 16 seconds to run.  Actually I had in
my head that I was trying to shrink the shape from the given shape, but
maybe I have it backwards and you want to grow the shape?  I also don't
know if you want or don't want rounding.  (The above solution can produce
rounding if you want it, but it needs to be reworked to grow the shape
rather than shrink it, or the rounding is on the inside.)

$fn=32;
minkowski(){
linear_extrude(height=.01)
difference(){
polygon(outside);
polygon(inside);
}
cylinder(r2=.2,r1=0, h=1);
}

http://forum.openscad.org/file/t2477/star3.png

That's faster, taking 8s.

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