I try to find simple beveal method and it seems now BOSL2 for cone. Correct?\ But if angle small enough I can use straght cylinders for join. \ \ And I cannot chamfer up of cylinder with BOSL2. So use 2 parts cylinder\ 

include <BOSL2/std.scad>

$fn=160;

ac = 1.8; // cone half angle

difference(){

   union(){

      xcyl(d=28,d1=60,l=600,circum=true,$fn=164);

      yrot(ac){

          up(23.9)zcyl(d=25,h=2.1,chamfer=1);

          join_prism(circle(d=25),base="cylinder",base_r=21.9,

                                 length=2, fillet=2, n=12);

           }

      xrot(90)right(80)yrot(1.8)join_prism(circle(d=20),base="cylinder",base_r=20-0.2,length=4, fillet=3, n=12,end_round=1);

     }

xcyl(d=28-6,d1=60-6,l=601,circum=true,$fn=164);

yrot(ac)up(20)zcyl(d=21,h=40);

xrot(90)right(80)yrot(1.8)up(20)zcyl(d=17,h=40);

}

``` include <BOSL2/std.scad> ``` ``` $fn=160; ``` ``` ac = 1.8; // cone half angle ``` ``` difference(){ ``` ``` union(){ ``` ``` xcyl(d=28,d1=60,l=600,circum=true,$fn=164); ``` ``` yrot(ac){ ``` ``` up(23.9)zcyl(d=25,h=2.1,chamfer=1); ``` ``` join_prism(circle(d=25),base="cylinder",base_r=21.9, ``` ``` length=2, fillet=2, n=12); ``` ``` } ``` ``` xrot(90)right(80)yrot(1.8)join_prism(circle(d=20),base="cylinder",base_r=20-0.2,length=4, fillet=3, n=12,end_round=1); ``` ``` } ``` ``` xcyl(d=28-6,d1=60-6,l=601,circum=true,$fn=164); ``` ``` yrot(ac)up(20)zcyl(d=21,h=40); ``` ``` xrot(90)right(80)yrot(1.8)up(20)zcyl(d=17,h=40); ``` ``` } ```

Peter Kriens

Adrian recently made a new function attach_prism that is perfect for this kind of work. If you use it with tube(), you can make your code look awfully clean. attach_prism is an easier to use front on joint_prism. Also take a look at prism_connector which allows you to connect different shapes without having to do trigonometry. These new modules use the facility to store the current geometry in a variable with the parent() function and parent_part() function. You can then later restore that geometry with restore(geometry). You can also now measure the distance between two anchors in different geometries. Peter Kriens include <BOSL2/std.scad> $fn = $preview ? 30 : 200; wall=1; diff() yrot(90) tube(od=25, wall=1, h=40) // base tube let(tube = parent(), inside = parent_part("inside")) attach_prism( // solid on tube circle(d=20), LEFT, l=5, fillet=2, overlap=0 ) attach( "end", BOT) tube( od=20, wall=wall, rounding2=0.5, l=1) // rounding at top tag("remove") restore(inside) attach_prism( // remove inside circle(d=20-2*wall), LEFT, l=5+desc_dist( tube, LEFT, inside,LEFT), fillet=2, ) attach( "end", BOT) tube( od=18,wall=1, l=1) ;  You can make the extrusion part in a module so it is easier to use: module outlet(d,l,where) { let(tube = parent(), inside = parent_part("inside")) attach_prism( // solid on tube circle(d=d), where, l=l, fillet=2, overlap=0 ) attach( "end", BOT) tube( od=d, wall=wall, rounding2=0.5, l=1) // rounding at top tag("remove") restore(inside) attach_prism( // solid on tube circle(d=d-2*wall), where, l=l+desc_dist(tube,where, inside,where), fillet=2, overlap=0 ) ; children(); } diff() yrot(90) tube(od=25, wall=1, h=40) // base tube for ( w=[0:45:359]) outlet(d=10,l=5,[cos(w), sin(w), 0]) ; 

ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478

I tried cone tube but got an error ``` ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478 ``` It seems currently impossible to use attach_xxxx with cones

Yes, unfortunately cones are not supported, only right-angle cylinders with attach_prism and prism_connector. On Fri, Nov 28, 2025 at 11:21 AM yur_vol--- via Discuss < discuss@lists.openscad.org> wrote: > I tried cone tube but got an error > > ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478 > > It seems currently impossible to use attach_xxxx with cones > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org

Peter

prism_connector and attach_prism work so amazingly well that the disappointment is always surprisingly deep if it doesn't work in a rare case ...  I almost exclusively use these functions now. The fact that they take a profile for the shape makes them extremely versatile and in most cases they are very easy to round with the rounded_prism that takes the same profile. But alas, conical shapes are not supported ... I guess it is really a lot harder. If we ask Adrian very very nicely ... :-) Peter > On 28 Nov 2025, at 17:21, yur_vol--- via Discuss <discuss@lists.openscad.org> wrote: > > I tried cone tube but got an error > > ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478 > It seems currently impossible to use attach_xxxx with cones > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org

It's not actually that cones are a lot harder. I think they are actually only a little bit harder fundamentally, but it requires completely new code. The problem is that join_prism doesn't support cones and it appears hard to add it there because of assumptions made about the geometry. It might be easier, actually, if I wrote an entirely separate module to join to cones just for prism_connector to invoke, I'm not sure. So while there's no reason it can't be done, it's a major effort to actually do it. On Sat, Nov 29, 2025 at 10:57 AM Peter Kriens via Discuss < discuss@lists.openscad.org> wrote: > > prism_connector and attach_prism work so amazingly well that the > disappointment is always surprisingly deep if it doesn't work in a rare > case ... > > [image: PastedGraphic-1.png] > > > I almost exclusively use these functions now. The fact that they take a > profile for the shape makes them extremely versatile and in most cases they > are very easy to round with the rounded_prism that takes the same profile. > > But alas, conical shapes are not supported ... I guess it is really a lot > harder. > > If we ask Adrian very very nicely ... :-) > > Peter > > > > > > > > On 28 Nov 2025, at 17:21, yur_vol--- via Discuss < > discuss@lists.openscad.org> wrote: > > I tried cone tube but got an error > > ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478 > > It seems currently impossible to use attach_xxxx with cones > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org > > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org

Peter

Peter

I recognize the problem. It is a petty since cone is quite common. Ah well, c'est la vie ... Peter > On 3 Dec 2025, at 23:07, Adrian Mariano via Discuss <discuss@lists.openscad.org> wrote: > > It's not actually that cones are a lot harder. I think they are actually only a little bit harder fundamentally, but it requires completely new code. The problem is that join_prism doesn't support cones and it appears hard to add it there because of assumptions made about the geometry. It might be easier, actually, if I wrote an entirely separate module to join to cones just for prism_connector to invoke, I'm not sure. So while there's no reason it can't be done, it's a major effort to actually do it. > > On Sat, Nov 29, 2025 at 10:57 AM Peter Kriens via Discuss <discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>> wrote: >> >> prism_connector and attach_prism work so amazingly well that the disappointment is always surprisingly deep if it doesn't work in a rare case ... >> >> <PastedGraphic-1.png> >> >> >> I almost exclusively use these functions now. The fact that they take a profile for the shape makes them extremely versatile and in most cases they are very easy to round with the rounded_prism that takes the same profile. >> >> But alas, conical shapes are not supported ... I guess it is really a lot harder. >> >> If we ask Adrian very very nicely ... :-) >> >> Peter >> >> >> >> >> >> >> >>> On 28 Nov 2025, at 17:21, yur_vol--- via Discuss <discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>> wrote: >>> >>> I tried cone tube but got an error >>> >>> ERROR: Assertion '(geom[1] == geom[2])' failed: "For anchors other than TOP/BOTTOM, cylinder must be non-conical, with same size at each end" in file ../../Users/123/Documents/OpenSCAD/libraries/BOSL2/rounding.scad, line 4478 >>> It seems currently impossible to use attach_xxxx with cones >>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org <mailto:discuss-leave@lists.openscad.org> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org <mailto:discuss-leave@lists.openscad.org>_______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org