Newbie with rotation problem
huh...that last doesn't work for me at all...I can kinda round part of the
primary object if I translate the sphere out to the coroner of the object
but still it only rounds part of it...
I admit I don't know much about full, so maybe there is some way to make it
work over the entire thing.
To my mind I would need a sphere at each vertex.
maybe minkowski() instead of hull()?
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On 01. april 2016 21:11, Ronaldo wrote:
Sorry. That is what I mean:
minkowski() {
sphere(1);
union() {
cylinder(r1=10,r2=0,h=10,$fn=4);
mirror([0,0,-1]) cylinder(r1=10,r2=0,h=10,$fn=4);
}
}
Interesting ... so minkowski does not really care about the
specification of the object type (cylinder), only the discretized result.
It appears to me to be a major hack to use cylinder to specify a cone
which becomes a pyramid and then use minkowski on that....
Carsten Arnholm
There are no true spheres, cylinders, circles or curves in OpenScad once
the renderings starts. All the geometry is represented by polygons and
polyhedra.
On 1 April 2016 at 20:45, Carsten Arnholm arnholm@arnholm.org wrote:
On 01. april 2016 21:11, Ronaldo wrote:
Sorry. That is what I mean:
minkowski() {
sphere(1);
union() {
cylinder(r1=10,r2=0,h=10,$fn=4);
mirror([0,0,-1]) cylinder(r1=10,r2=0,h=10,$fn=4);
}
}
Interesting ... so minkowski does not really care about the specification
of the object type (cylinder), only the discretized result.
It appears to me to be a major hack to use cylinder to specify a cone
which becomes a pyramid and then use minkowski on that....
Carsten Arnholm
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I generally use $fn=100; as the first line in my projects, setting it at a
global level. With hull(), it then gives a nice, round shape. The minkowski
version also gives a good-looking result but when I subtract them from one
another by using:
$fn=100;
radius=10;
difference(){
hull(){
translate([radius-1, 0, 0]) sphere(1);
translate([-radius-1, 0, 0]) sphere(1);
translate([0, radius-1, 0]) sphere(1);
translate([0, -radius-1, 0]) sphere(1);
translate([0, 0, radius-1]) sphere(1);
translate([0, 0, -radius-1]) sphere(1);
}
minkowski() {
sphere(1);
union() {
cylinder(r1=radius, r2=0, h=radius, $fn=4);
mirror([0,0,-1]) cylinder(r1=radius, r2=0, h=radius, $fn=4);
}
}
}
Then it seems the minkowski version is a bit wrong. The hull version touches
the axes at exactly 10 but the minkowski is too long on the negative sides.
Thus, the minkowski version doesn't seem to have the same length sides.
(The hull version needs radius-1 because the spheres also take space, and
they have a radius of 1. Total makes the exact radius.
With kind regards,
Wim,
W.A. ten Brink
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Oops, one minus needs to be a +. :)
With kind regards,
Wim,
W.A. ten Brink
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nophead wrote
There are no true spheres, cylinders, circles or curves in OpenScad once
the renderings starts. All the geometry is represented by polygons and
polyhedra.
This is a quiz :) The following image is the preview of translated
primitives. No boolean operations, no rotation, neither scale nor mirror.
How to get them?
http://forum.openscad.org/file/n16907/primitives.png
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It would appear that a good part of the answer to your question lies here:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Primitive_Solids
Some of the answer involves low values of $fn along with cylinders of
different r1 and r2 values.
Do you already know the answers and this is a true quiz, or are you seeking
a solution?
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The second from the left is a sphere.
All the rest could be done using cylinder.
The middle could be a cube.
The second from right could be a sphere.
See how OpenSCAD has warped me? When I first started using OpenSCAD, I was
really annoyed by all of this. I wanted sphere to always produce a sphere,
cylinder to always produce a cylinder, etc.
I am still in favour of adding prism(), pyramid() and cone(), even though
you would normally do those using cylinder().
On 2 April 2016 at 14:21, Ronaldo rcmpersiano@gmail.com wrote:
nophead wrote
There are no true spheres, cylinders, circles or curves in OpenScad once
the renderings starts. All the geometry is represented by polygons and
polyhedra.
This is a quiz :) The following image is the preview of translated
primitives. No boolean operations, no rotation, neither scale nor mirror.
How to get them?
http://forum.openscad.org/file/n16907/primitives.png
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On Sat, Apr 02, 2016 at 02:57:39PM -0400, doug moen wrote:
See how OpenSCAD has warped me? When I first started using OpenSCAD, I was
really annoyed by all of this. I wanted sphere to always produce a sphere,
cylinder to always produce a cylinder, etc.
IMHO, it is fine if openscad has to "simplify" cylinders to extruded
polygons. However, in writing code, it would be best to assume that
the implementation reserves the right to use the simplification OR
BETTER.
That means that the triangular prism could suddenly upgrade to a
perfect cylinder if say the output format directly supports cylinders.
But alas, it has become customary to exploit the defects of the
implementation so that now there is no way back.
I am still in favour of adding prism(), pyramid() and cone(), even though
you would normally do those using cylinder().
Those would, be oneliner modules, right? There is a "system" library
now, so it could be added there, right?
Roger.
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fred_dot_u wrote
It would appear that a good part of the answer to your question lies here:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Primitive_Solids
Some of the answer involves low values of $fn along with cylinders of
different r1 and r2 values.
Do you already know the answers and this is a true quiz, or are you
seeking a solution?
You are right. I generated the image so it is really a quiz.
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