Bevelling a cylinder creates a void
I'm trying to bevel a drilled cylinder, but I when I do that, the top
of the cylinder disappears into a (green) hole. I attached a
screenshot. The 3D printer-owning friend I sent my STL to says there's
a strange gap at the top.
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
Of course, if I remove the bevel, the top of the cylinder is normal (yellow).
Is this a bug? Is there a better way to bevel a cylinder?
--
Luc Le Blanc
The model works for me. What version of OpenSCAD are you using?
lleblanc wrote
I'm trying to bevel a drilled cylinder, but I when I do that, the top
of the cylinder disappears into a (green) hole. I attached a
screenshot. The 3D printer-owning friend I sent my STL to says there's
a strange gap at the top.
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
Of course, if I remove the bevel, the top of the cylinder is normal
(yellow).
Is this a bug? Is there a better way to bevel a cylinder?
--
Luc Le Blanc
OpenSCAD mailing list
Discuss@.openscad
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bevel.png (9K)
<http://forum.openscad.org/attachment/31592/0/bevel.png>
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When I run your code on my machine (Win7, OpenSCAD 2019.05) everything is fine. The exported STL passes Meshmixer inspector (watertight/manifold) and would likely print fine.
On Saturday, January 16, 2021, 11:58:40 AM EST, adrianv <avm4@cornell.edu> wrote:
The model works for me. What version of OpenSCAD are you using?
lleblanc wrote
I'm trying to bevel a drilled cylinder, but I when I do that, the top
of the cylinder disappears into a (green) hole. I attached a
screenshot. The 3D printer-owning friend I sent my STL to says there's
a strange gap at the top.
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
Of course, if I remove the bevel, the top of the cylinder is normal
(yellow).
Is this a bug? Is there a better way to bevel a cylinder?
--
Luc Le Blanc
OpenSCAD mailing list
Discuss@.openscad
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
bevel.png (9K)
<http://forum.openscad.org/attachment/31592/0/bevel.png>
--
Sent from: http://forum.openscad.org/
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I tried playing with the code and I get some rather strange F5 previews but the F6 render is OK using 2021.01.13 (git 0f79135ef)
difference(){
linear_extrude(39){
difference(){
circle(d=13.69);
circle(d=4);
}
}
// bevel
translate([13.69/2,0,39]) rotate([0,-56.89,0]) cylinder(d=60,h=15);
}
On 16 Jan 2021, at 17:03, fred via Discuss discuss@lists.openscad.org wrote:
When I run your code on my machine (Win7, OpenSCAD 2019.05) everything is fine. The exported STL passes Meshmixer inspector (watertight/manifold) and would likely print fine.
On Saturday, January 16, 2021, 11:58:40 AM EST, adrianv avm4@cornell.edu wrote:
The model works for me. What version of OpenSCAD are you using?
lleblanc wrote
I'm trying to bevel a drilled cylinder, but I when I do that, the top
of the cylinder disappears into a (green) hole. I attached a
screenshot. The 3D printer-owning friend I sent my STL to says there's
a strange gap at the top.
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
Of course, if I remove the bevel, the top of the cylinder is normal
(yellow).
Is this a bug? Is there a better way to bevel a cylinder?
--
Luc Le Blanc
OpenSCAD mailing list
Discuss@.openscad mailto:Discuss@.openscad
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
bevel.png (9K)
<http://forum.openscad.org/attachment/31592/0/bevel.png> http://forum.openscad.org/attachment/31592/0/bevel.png%3E
--
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I find that when subtracting shapes, you need to make them longer than
what you are subtracting the shape from. If both edges are on the same
plane, it often has no idea what to do, you can see the flashing
yellow/green of indecision...
On 16/01/2021 16:35, Luc Le
On 16/01/2021 16:35, Luc Le Blanc wrote:
I'm trying to bevel a drilled cylinder, but I when I do that, the top
of the cylinder disappears into a (green) hole. I attached a
screenshot. The 3D printer-owning friend I sent my STL to says there's
a strange gap at the top.
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
Of course, if I remove the bevel, the top of the cylinder is normal (yellow).
Is this a bug? Is there a better way to bevel a cylinder?
OpenSCAD mailing list
Discuss@lists.openscad.org
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make the last line -
translate([0,0,-2]) cylinder(h=40, d=4);
On 16/01/2021 16:35, Luc Le Blanc wrote:
$fn=100;
difference()
{
difference()
{
cylinder(h=39, d=13.69);
// bevel
translate([-6.845,-15,18])
{
rotate(a=[0,-56.89,0])
{
cube(30);
}
}
}
// bolt hole
cylinder(h=39, d=4);
}
I get weird behavior like that with the 2019.05 version as well as the RC5
version. It also persists if I shrink the cutting cylinder down to a
smaller diameter. I've seen weird preview behavior when the cutting object
is really big (like bigger than the viewport) but not in a case like this,
that I can remember.
It's bizarre that it works fine if you do the difference() in 3d but gives
those weird results when you use the more efficient technique of doing the
difference in 2d.
One other remark to the original poster: When you do a difference it's
normal for the cut surface to be green.
I tried playing with the code and I get some rather strange F5 previews but
the F6 render is OK using 2021.01.13 (git 0f79135ef)
difference(){
linear_extrude(39){
difference(){
circle(d=13.69);
circle(d=4);
}
}
// bevel
translate([13.69/2,0,39]) rotate([0,-56.89,0]) cylinder(d=60,h=15);
}
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That is to low convexity, default should be much higher but it is what it is
.
difference(){
linear_extrude(39,convexity=10){
difference(){
circle(d=13.69);
circle(d=4);
}
}
// bevel
translate([13.69/2,0,39]) rotate([0,-56.89,0]) cylinder(d=60,h=15);
}
--
Sent from: http://forum.openscad.org/
I never remember convexity. I have it set to 10 in all my library functions,
and I've never noticed that this causes any problems or performance issues.
Is there some reason the default couldn't be changed in a future version of
OpenSCAD? Why would anybody need convexity to be low?
TLC123 wrote
That is to low convexity, default should be much higher but it is what it
is
.
difference(){
linear_extrude(39,convexity=10){
difference(){
circle(d=13.69);
circle(d=4);
}
}
// bevel
translate([13.69/2,0,39]) rotate([0,-56.89,0])
cylinder(d=60,h=15);
}
--
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I think because 1 is the fastest and is correct for all the builtin solids.
Odd thing is that the number required seems to be PC dependent. On an old
laptop I had to set it higher!
On Sat, 16 Jan 2021 at 18:29, adrianv avm4@cornell.edu wrote:
I never remember convexity. I have it set to 10 in all my library
functions,
and I've never noticed that this causes any problems or performance
issues.
Is there some reason the default couldn't be changed in a future version of
OpenSCAD? Why would anybody need convexity to be low?
TLC123 wrote
That is to low convexity, default should be much higher but it is what
it
is
.
difference(){
linear_extrude(39,convexity=10){
difference(){
circle(d=13.69);
circle(d=4);
}
}
// bevel
translate([13.69/2,0,39]) rotate([0,-56.89,0])
cylinder(d=60,h=15);
}
--
Sent from: http://forum.openscad.org/
OpenSCAD mailing list
Discuss@.openscad
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