Even though I am a noobie, it looks like I've run across some apparent issues
in BOSL2/gears.scad
When using anchor=TOP" or BOTTOM, or "flattop" in bevel_gear(), the
resulting translation is incorrect:
Here is my example code:
$fn = 24;
include <BOSL2/std.scad>;
include <BOSL2/gears.scad>;
include <BOSL2/attachments.scad>;
#bevel_gear(
pitch=5, teeth=36, face_width=20, shaft_diam=5,
pitch_angle=45, spiral_angle=0, anchor=BOTTOM // or TOP, or "flattop"
);
When using anchor=TOP or "flattop", the gear top is just above the axis, as
shown in the first image.
http://forum.openscad.org/file/t3150/AnchorTop.png
When using anchor=BOTTOM, the gear bottom is just below the axis, as shown
in the second image.
http://forum.openscad.org/file/t3150/AnchorBOTTOM.png
This issue seems to be caused by the fact that the "thickness" variable is
calculated differently in the bevel_gear() function...
Line 963: thickness = abs(verts1[0][0].z - select(verts1,-1)[0].z),
...than it is in the bevel_gear() module...
Line 1028: thickness = face_width * cos(pitch_angle);
As someone who is very new to OpenSCAD and BOSL2, my question is:
Q. Is this truly a bug, or am I misinterpreting what anchor is meant to do?
A secondary consequence of this is that the true thickness of the gear is
not available to the user.
When using anchor="apex" to get a correctly matched pair of bevels, as far
as I can tell, the user MUST have access to the true thickness and/or the
distance from the apex to (at least) one face of the gear to correctly place
the gears in an assembly. This suggested that one or more bevel-gear
informational functions may need to be added.
Your thoughts?
--
Sent from: http://forum.openscad.org/
To me it looks like a bug. Worse: if you try to render the gear with F6 it
fails--that's definitely a bug. You can submit an issue on github.
LenStruttmann wrote
Even though I am a noobie, it looks like I've run across some apparent
issues
in BOSL2/gears.scad
When using anchor=TOP" or BOTTOM, or "flattop" in bevel_gear(), the
resulting translation is incorrect:
Your thoughts?
--
Sent from: http://forum.openscad.org/
OpenSCAD mailing list
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--
Sent from: http://forum.openscad.org/
Thanks!
On Mon, Mar 29, 2021 at 3:46 PM adrianv avm4@cornell.edu wrote:
To me it looks like a bug. Worse: if you try to render the gear with F6
it fails--that's definitely a bug. You can submit an issue on github.
LenStruttmann wrote
Even though I am a noobie, it looks like I've run across some apparent
issues
in BOSL2/gears.scad
When using anchor=TOP" or BOTTOM, or "flattop" in bevel_gear(), the
resulting translation is incorrect:
Your thoughts?
--
Sent from: http://forum.openscad.org/
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