Trig, hmm. There's a mnemonic we were taught which I still remember: SOHCAHTOA or sin (angle) = OPPOSITE/HYPOTENUSE or cos (angle) = ADJACENT/HYPOTENUSE or tan (angle) =OPPOSITE/ADJACENT Remembering the mnemonic is easier, for my grey cells.  I've probably used that more since taking up OpenSCAD than in the previous 50+ years, I used it last week, to calculate the length of a line from a 3D object rotated along an axis and projected onto the XY plane.  All so I could put holes in right place. Roger. On 25/09/2025 08:30, discuss-request@lists.openscad.org wrote: > Re: sweep in BOSL2

Excellent mnemonic! Thanks! On Thu, Sep 25, 2025 at 8:48 AM Roger Whiteley via Discuss < discuss@lists.openscad.org> wrote: > Trig, hmm. > > There's a mnemonic we were taught which I still remember: > > SOHCAHTOA > > or sin (angle) = OPPOSITE/HYPOTENUSE > > or cos (angle) = ADJACENT/HYPOTENUSE > > or tan (angle) =OPPOSITE/ADJACENT > > Remembering the mnemonic is easier, for my grey cells. I've probably > used that more since taking up OpenSCAD than in the previous 50+ years, > I used it last week, to calculate the length of a line from a 3D object > rotated along an axis and projected onto the XY plane. All so I could > put holes in right place. > > Roger. > > > On 25/09/2025 08:30, discuss-request@lists.openscad.org wrote: > > Re: sweep in BOSL2 > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org

On Thu, 2025-09-25 at 14:48 +0100, Roger Whiteley via Discuss wrote: > Trig, hmm. > > There's a mnemonic we were taught which I still remember: > > SOHCAHTOA > > or sin (angle) = OPPOSITE/HYPOTENUSE > > or cos (angle) = ADJACENT/HYPOTENUSE > > or tan (angle) =OPPOSITE/ADJACENT > > Remembering the mnemonic is easier, for my grey cells.  I've probably > used that more since taking up OpenSCAD than in the previous 50+ years, > I used it last week, to calculate the length of a line from a 3D object > rotated along an axis and projected onto the XY plane.  All so I could > put holes in right place. Nice, but there's little chance I could remember it, and even less chance I could apply it. I will never forget how to look it up in BOSL2 or in an online triangle calculator. L

There seem to be people who get a kick out of solving trig problems when building their models. I would rather focus on the geometry when building a model rather than computational details and I tend to think that one of the jobs of BOSL2 is to do the trig for you. In some sense in you have to resort to using trig it is a failure of the library. On Thu, Sep 25, 2025 at 11:38 larry via Discuss <discuss@lists.openscad.org> wrote: > On Thu, 2025-09-25 at 14:48 +0100, Roger Whiteley via Discuss wrote: > > Trig, hmm. > > > > There's a mnemonic we were taught which I still remember: > > > > SOHCAHTOA > > > > or sin (angle) = OPPOSITE/HYPOTENUSE > > > > or cos (angle) = ADJACENT/HYPOTENUSE > > > > or tan (angle) =OPPOSITE/ADJACENT > > > > Remembering the mnemonic is easier, for my grey cells. I've probably > > used that more since taking up OpenSCAD than in the previous 50+ years, > > I used it last week, to calculate the length of a line from a 3D object > > rotated along an axis and projected onto the XY plane. All so I could > > put holes in right place. > > Nice, but there's little chance I could remember it, and even less > chance I could apply it. > > I will never forget how to look it up in BOSL2 or in an online triangle > calculator. > > L > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org