E
emmanueliarussi
Tue, Jan 3, 2017 1:58 PM
Hello,
I was wondering if there is a way in OpenSCAD to get the projection volume
of a shape.
Let's say I have an imported mesh, I want the volume generated by projecting
it onto a plane (xy in my case). Thanks!
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Hello,
I was wondering if there is a way in OpenSCAD to get the projection volume
of a shape.
Let's say I have an imported mesh, I want the volume generated by projecting
it onto a plane (xy in my case). Thanks!
--
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MK
Marius Kintel
Tue, Jan 3, 2017 2:35 PM
You cannot measure the volume in OpenSCAD, but you can create the shape like this:
module MyShape() translate([0,0,30]) sphere(20);
hull() {
MyShape();
linear_extrude(height=1) projection() MyShape();
}
-Marius
On Jan 3, 2017, at 08:58, emmanueliarussi emmanueliarussi@gmail.com wrote:
Hello,
I was wondering if there is a way in OpenSCAD to get the projection volume
of a shape.
Let's say I have an imported mesh, I want the volume generated by projecting
it onto a plane (xy in my case). Thanks!
You cannot measure the volume in OpenSCAD, but you can create the shape like this:
module MyShape() translate([0,0,30]) sphere(20);
hull() {
MyShape();
linear_extrude(height=1) projection() MyShape();
}
-Marius
On Jan 3, 2017, at 08:58, emmanueliarussi <emmanueliarussi@gmail.com> wrote:
>
> Hello,
> I was wondering if there is a way in OpenSCAD to get the projection volume
> of a shape.
> Let's say I have an imported mesh, I want the volume generated by projecting
> it onto a plane (xy in my case). Thanks!
E
emmanueliarussi
Tue, Jan 3, 2017 2:52 PM
Right, that's the way I'm doing it now, but only works for convex shapes (as
the sphere). Otherwise, the hull() destroys the non-convexities and holes in
the original shape. I was looking for a more general solution.
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Right, that's the way I'm doing it now, but only works for convex shapes (as
the sphere). Otherwise, the hull() destroys the non-convexities and holes in
the original shape. I was looking for a more general solution.
--
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RP
Ronaldo Persiano
Tue, Jan 3, 2017 3:03 PM
A very slow solution that works with non-convex shapes is:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
intersection() {
minkowski() {
MyShape();
translate([0,0,-100]) cylinder(d=0.001,h=100);
}
translate([0,0,50]) cube([100,100,100],center=true);
}
2017-01-03 12:52 GMT-02:00 emmanueliarussi emmanueliarussi@gmail.com:
A very slow solution that works with non-convex shapes is:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
intersection() {
minkowski() {
MyShape();
translate([0,0,-100]) cylinder(d=0.001,h=100);
}
translate([0,0,50]) cube([100,100,100],center=true);
}
2017-01-03 12:52 GMT-02:00 emmanueliarussi <emmanueliarussi@gmail.com>:
> Right, that's the way I'm doing it now, but only works for convex shapes
> (as
> the sphere). Otherwise, the hull() destroys the non-convexities and holes
> in
> the original shape. I was looking for a more general solution.
>
>
>
> --
> View this message in context: http://forum.openscad.org/Projection-volume-
> tp19885p19887.html
> Sent from the OpenSCAD mailing list archive at Nabble.com.
>
> _______________________________________________
> OpenSCAD mailing list
> Discuss@lists.openscad.org
> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>
E
emmanueliarussi
Tue, Jan 3, 2017 3:52 PM
That did the trick. Thanks a lot Ronaldo! I'll now try to run my code in a
faster computer.
Ronaldo wrote
A very slow solution that works with non-convex shapes is:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
intersection() {
minkowski() {
MyShape();
translate([0,0,-100]) cylinder(d=0.001,h=100);
}
translate([0,0,50]) cube([100,100,100],center=true);
}
2017-01-03 12:52 GMT-02:00 emmanueliarussi <
Right, that's the way I'm doing it now, but only works for convex shapes
(as
the sphere). Otherwise, the hull() destroys the non-convexities and holes
in
the original shape. I was looking for a more general solution.
--
View this message in context:
http://forum.openscad.org/Projection-volume-
tp19885p19887.html
Sent from the OpenSCAD mailing list archive at Nabble.com.
OpenSCAD mailing list
That did the trick. Thanks a lot Ronaldo! I'll now try to run my code in a
faster computer.
Ronaldo wrote
> A very slow solution that works with non-convex shapes is:
>
> module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
> sphere(20); }
>
> intersection() {
> minkowski() {
> MyShape();
> translate([0,0,-100]) cylinder(d=0.001,h=100);
> }
> translate([0,0,50]) cube([100,100,100],center=true);
> }
>
> 2017-01-03 12:52 GMT-02:00 emmanueliarussi <
> emmanueliarussi@
> >:
>
>> Right, that's the way I'm doing it now, but only works for convex shapes
>> (as
>> the sphere). Otherwise, the hull() destroys the non-convexities and holes
>> in
>> the original shape. I was looking for a more general solution.
>>
>>
>>
>> --
>> View this message in context:
>> http://forum.openscad.org/Projection-volume-
>> tp19885p19887.html
>> Sent from the OpenSCAD mailing list archive at Nabble.com.
>>
>> _______________________________________________
>> OpenSCAD mailing list
>>
> Discuss@.openscad
>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>>
>
> _______________________________________________
> OpenSCAD mailing list
> Discuss@.openscad
> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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P
Parkinbot
Tue, Jan 3, 2017 4:50 PM
Just another good reason for generalizing the implementation of
linear_extrude() to operate over 3D-objects. We had some discussion about
this, see
http://forum.openscad.org/Non-Linear-Transformations-tp14539p16673.html
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Just another good reason for generalizing the implementation of
linear_extrude() to operate over 3D-objects. We had some discussion about
this, see
http://forum.openscad.org/Non-Linear-Transformations-tp14539p16673.html
--
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NH
nop head
Tue, Jan 3, 2017 5:06 PM
I think this gives the correct result in a timely manner:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
eps = 1/80;
inf = 100;
intersection() {
hull() {
MyShape();
linear_extrude(height = eps, convexity = 2)
projection()
MyShape();
}
linear_extrude(height = inf, convexity = 2)
projection()
MyShape();
}
On 3 January 2017 at 16:50, Parkinbot rudolf@parkinbot.com wrote:
I think this gives the correct result in a timely manner:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
eps = 1/80;
inf = 100;
intersection() {
hull() {
MyShape();
linear_extrude(height = eps, convexity = 2)
projection()
MyShape();
}
linear_extrude(height = inf, convexity = 2)
projection()
MyShape();
}
On 3 January 2017 at 16:50, Parkinbot <rudolf@parkinbot.com> wrote:
> Just another good reason for generalizing the implementation of
> linear_extrude() to operate over 3D-objects. We had some discussion about
> this, see
> http://forum.openscad.org/Non-Linear-Transformations-tp14539p16673.html
>
>
>
> --
> View this message in context: http://forum.openscad.org/Projection-volume-
> tp19885p19892.html
> Sent from the OpenSCAD mailing list archive at Nabble.com.
>
> _______________________________________________
> OpenSCAD mailing list
> Discuss@lists.openscad.org
> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>
NH
nop head
Tue, Jan 3, 2017 5:09 PM
I think this gives the correct result in a timely manner:
module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
sphere(20); }
eps = 1/80;
inf = 100;
intersection() {
hull() {
MyShape();
linear_extrude(height = eps, convexity = 2)
projection()
MyShape();
}
linear_extrude(height = inf, convexity = 2)
projection()
MyShape();
}
On 3 January 2017 at 16:50, Parkinbot rudolf@parkinbot.com wrote:
Or perhaps not, sorry!
On 3 January 2017 at 17:06, nop head <nop.head@gmail.com> wrote:
> I think this gives the correct result in a timely manner:
>
> module MyShape() { translate([0,0,30]) sphere(20); translate([0,15,20])
> sphere(20); }
>
> eps = 1/80;
> inf = 100;
>
> intersection() {
> hull() {
> MyShape();
>
> linear_extrude(height = eps, convexity = 2)
> projection()
> MyShape();
> }
> linear_extrude(height = inf, convexity = 2)
> projection()
> MyShape();
> }
>
>
> On 3 January 2017 at 16:50, Parkinbot <rudolf@parkinbot.com> wrote:
>
>> Just another good reason for generalizing the implementation of
>> linear_extrude() to operate over 3D-objects. We had some discussion about
>> this, see
>> http://forum.openscad.org/Non-Linear-Transformations-tp14539p16673.html
>>
>>
>>
>> --
>> View this message in context: http://forum.openscad.org/Proj
>> ection-volume-tp19885p19892.html
>> Sent from the OpenSCAD mailing list archive at Nabble.com.
>>
>> _______________________________________________
>> OpenSCAD mailing list
>> Discuss@lists.openscad.org
>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>>
>
>
R
Ronaldo
Tue, Jan 3, 2017 5:33 PM
Or a good reason to generalize minkowski to accept 1D and 2D objects as well
defined in mathematics. The minkowski of a line segment and a solid is much
easier to compute.
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Parkinbot wrote
> Just another good reason for generalizing the implementation of
> linear_extrude() to operate over 3D-objects. We had some discussion about
> this, see
> http://forum.openscad.org/Non-Linear-Transformations-tp14539p16673.html
Or a good reason to generalize minkowski to accept 1D and 2D objects as well
defined in mathematics. The minkowski of a line segment and a solid is much
easier to compute.
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P
Parkinbot
Tue, Jan 3, 2017 10:26 PM
Or a good reason to generalize minkowski to accept 1D and 2D objects as
well defined in mathematics. The minkowski of a line segment and a solid
is much easier to compute.
This would mean to include 1D objects into OpenSCAD first and
redefine/expand/reimplement all operations and so on, as already discussed.
A lot of work.
BTW, letting scale and twist aside linear_extrude() IS a minkowski_z()
operator. While it is easy to implement for 2D objects, implementing it on
general 3D objects can get nasty.
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Ronaldo wrote
> Or a good reason to generalize minkowski to accept 1D and 2D objects as
> well defined in mathematics. The minkowski of a line segment and a solid
> is much easier to compute.
This would mean to include 1D objects into OpenSCAD first and
redefine/expand/reimplement all operations and so on, as already discussed.
A lot of work.
BTW, letting scale and twist aside linear_extrude() IS a minkowski_z()
operator. While it is easy to implement for 2D objects, implementing it on
general 3D objects can get nasty.
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