Cant smooth this domed end
Below is a very cut down sample of my model. which in reality is doing
rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that I
seem to be unable to smooth out the 'tree rings' on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother.
I've also experimented with $fn and the end gets smoother up to a value of
about 570 and then it gets worse. Messing with $fs doesn't seem to help
either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
How smooth do you need it? It looks very smooth to me with $fn = 1000.
[image: image.png]
On Thu, 10 Jan 2019 at 18:56, Andy Carlson andycarlson@acm.org wrote:
Below is a very cut down sample of my model… which in reality is doing
rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that
I seem to be unable to smooth out the ‘tree rings’ on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother.
I’ve also experimented with $fn and the end gets smoother up to a value of
about 570 and then it gets worse. Messing with $fs doesn’t seem to help
either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Which version of OpenSCAD are you using? There used to be a bug which
limited the fine detail of 2D objects. That might have caused tree rings.
On Thu, 10 Jan 2019 at 19:02, nop head nop.head@gmail.com wrote:
How smooth do you need it? It looks very smooth to me with $fn = 1000.
[image: image.png]
On Thu, 10 Jan 2019 at 18:56, Andy Carlson andycarlson@acm.org wrote:
Below is a very cut down sample of my model… which in reality is doing
rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that
I seem to be unable to smooth out the ‘tree rings’ on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother.
I’ve also experimented with $fn and the end gets smoother up to a value of
about 570 and then it gets worse. Messing with $fs doesn’t seem to help
either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Here are my notes:
-
I could not see the artifacts you have noticed with the rotate_extrude;
the extrusion seems to be smooth; I am using OpenSCAD
http://www.openscad.org version 2018.01.06*;* -
the render of the import polygon of end-dome.dxf (without extrusion)
shows a series of concavities along the rounded part for $fn values greater
than 150 as shown bellow:
[image: end-dome-dxf.PNG]
these artifacts are not present in the dxf when viewed with LibreCAD;
- I could "fill" those concavities with a tricky code that makes the
hull() of just that section of the polygon:
module endDome() import("end-dome.dxf", $fn=1000);
difference(){
hull() endDome();
translate([0,-9.9]) square([2.7, 10]);
}
intersection() {
endDome();
translate([0,-9.9]) square([2.7, 10]);
}
after that, I could generate a new dxf of a new polygon;
- the render of the new dxf does not show any artifact.
My conclusion: there is something in your dxf file that is not digestible
by OpenSCAD.
The trick I have used to "clean" end-dome.dxf may be applied to other files
in a case by case basis but it is not neither general nor easy.
For your consideration I have attached the new dxf.
Em qui, 10 de jan de 2019 às 18:56, Andy Carlson andycarlson@acm.org
escreveu:
Below is a very cut down sample of my model… which in reality is doing
rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that
I seem to be unable to smooth out the ‘tree rings’ on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother.
I’ve also experimented with $fn and the end gets smoother up to a value of
about 570 and then it gets worse. Messing with $fs doesn’t seem to help
either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Thanks for your reply and effort on this.
While I would not rule out an issue specific to the DXF import or my DXF file in particular, I’ve completely eliminated that DXF from my full model and redrawn the dome using OpenSCAD primitives.
The ‘primitives’ version is nice and smooth when run on its own but when added back into the full model (and the dome DXF removed), the tree rings are still there.
I think you may be right about concavity. I suspected that the tree rings may involve the edges of some rings being indented but it’s difficult to be certain.
Regards, Andy
From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of Ronaldo Persiano
Sent: 12 January 2019 19:56
To: OpenSCAD general discussion discuss@lists.openscad.org
Subject: Re: [OpenSCAD] Cant smooth this domed end
Here are my notes:
-
I could not see the artifacts you have noticed with the rotate_extrude; the extrusion seems to be smooth; I am using http://www.openscad.org OpenSCAD version 2018.01.06;
-
the render of the import polygon of end-dome.dxf (without extrusion) shows a series of concavities along the rounded part for $fn values greater than 150 as shown bellow:
these artifacts are not present in the dxf when viewed with LibreCAD;
- I could "fill" those concavities with a tricky code that makes the hull() of just that section of the polygon:
module endDome() import("end-dome.dxf", $fn=1000);
difference(){
hull() endDome();
translate([0,-9.9]) square([2.7, 10]);
}
intersection() {
endDome();
translate([0,-9.9]) square([2.7, 10]);
}
after that, I could generate a new dxf of a new polygon;
- the render of the new dxf does not show any artifact.
My conclusion: there is something in your dxf file that is not digestible by OpenSCAD.
The trick I have used to "clean" end-dome.dxf may be applied to other files in a case by case basis but it is not neither general nor easy.
For your consideration I have attached the new dxf.
Em qui, 10 de jan de 2019 às 18:56, Andy Carlson <andycarlson@acm.org mailto:andycarlson@acm.org > escreveu:
Below is a very cut down sample of my model… which in reality is doing rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that I seem to be unable to smooth out the ‘tree rings’ on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother. I’ve also experimented with $fn and the end gets smoother up to a value of about 570 and then it gets worse. Messing with $fs doesn’t seem to help either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
OpenSCAD mailing list
Discuss@lists.openscad.org mailto:Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
I think the DXF import draws arcs with the normal $fn, $fs, $fa settings
but it then snaps it to a coarse grid, which is 1/1024. I don't think that
is done anywhere else. The normal grid is 1024 times less than that. I.e.
about nano metres instead of microns.
On Sat, 12 Jan 2019 at 20:11, Andy Carlson andycarlson@acm.org wrote:
Thanks for your reply and effort on this.
While I would not rule out an issue specific to the DXF import or my DXF
file in particular, I’ve completely eliminated that DXF from my full model
and redrawn the dome using OpenSCAD primitives.
The ‘primitives’ version is nice and smooth when run on its own but when
added back into the full model (and the dome DXF removed), the tree rings
are still there.
I think you may be right about concavity. I suspected that the tree rings
may involve the edges of some rings being indented but it’s difficult to be
certain.
Regards, Andy
From: Discuss [mailto:discuss-bounces@lists.openscad.org] *On Behalf Of
*Ronaldo Persiano
Sent: 12 January 2019 19:56
To: OpenSCAD general discussion discuss@lists.openscad.org
Subject: Re: [OpenSCAD] Cant smooth this domed end
Here are my notes:
-
I could not see the artifacts you have noticed with the rotate_extrude;
the extrusion seems to be smooth; I am using OpenSCAD
http://www.openscad.org version 2018.01.06*;* -
the render of the import polygon of end-dome.dxf (without extrusion)
shows a series of concavities along the rounded part for $fn values greater
than 150 as shown bellow:
[image: end-dome-dxf.PNG]
these artifacts are not present in the dxf when viewed with LibreCAD;
- I could "fill" those concavities with a tricky code that makes the
hull() of just that section of the polygon:
module endDome() import("end-dome.dxf", $fn=1000);
difference(){
hull() endDome();
translate([0,-9.9]) square([2.7, 10]);
}
intersection() {
endDome();
translate([0,-9.9]) square([2.7, 10]);
}
after that, I could generate a new dxf of a new polygon;
- the render of the new dxf does not show any artifact.
My conclusion: there is something in your dxf file that is not digestible
by OpenSCAD.
The trick I have used to "clean" end-dome.dxf may be applied to other
files in a case by case basis but it is not neither general nor easy.
For your consideration I have attached the new dxf.
Em qui, 10 de jan de 2019 às 18:56, Andy Carlson andycarlson@acm.org
escreveu:
Below is a very cut down sample of my model… which in reality is doing
rotate_extrude on a DXF.
It creates a cylinder with a shallow dome on the end. The trouble is that
I seem to be unable to smooth out the ‘tree rings’ on the end sufficiently.
If I reduce $fa to 0.5 then the end becomes coarser instead of smoother.
I’ve also experimented with $fn and the end gets smoother up to a value of
about 570 and then it gets worse. Messing with $fs doesn’t seem to help
either.
Is there anything I can do to get past this problem?
$fs=.05;
$fa=.632;
rotate_extrude(convexity=10) {
intersection() {
circle(16.9);
translate([-3,0,0]) {
square([3,20]);
}
}
}
Regards,
Andy
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
