[OpenSCAD] Newbie rotation confusion.

nop head nop.head at gmail.com
Fri Sep 7 06:38:15 EDT 2018


A cube has 8 corners but there are only 6 points if one is on each half
axis.

An object with all corners on an axis has triangular faces and looks like
this:




On 7 September 2018 at 11:26, Rogier Wolff <R.E.Wolff at bitwizard.nl> wrote:

> On Fri, Sep 07, 2018 at 10:47:15AM +0100, nop head wrote:
> > >Is there a simple way to get a cube at the origin with it's corners on
> the
> > axes?
> >
> > No it is physically impossible.
>
> Technically correct, but
>
> rotate ([0,atan (sqrt(2)),0])
>   rotate ([0,0,45])
>     cube (40, center=true);
>
> is what he was asking for.... I think.
>
> Roger.
>
>
> >
> > On 7 September 2018 at 10:06, Aurum <pommie.mike at gmail.com> wrote:
> >
> > > Having now subscribed to the mailing list hopefully this will now be
> > > posted.
> > > Sorry if it's posted twice.
> > >
> > > What I'm trying to do is understand how to get a cube at the origin
> with
> > > it's corners on the axes.
> > >
> > > Firstly, I tried rotating by 45° about x and y with no success.
> > >
> > > I then rotated 45° about the X axis with
> > > rotate(45,[1,0,0]){
> > >     color("cyan") cube(10,center=true);
> > > }
> > > and looked down the Y axis. What I see is this.
> > > <http://forum.openscad.org/file/t2335/cube1.png>
> > >
> > > I now realize that I'm not looking at a square anymore but a rectangle
> with
> > > sides 10 and 14.14 (10 x root 2) and so to align the corners with the Z
> > > axis
> > > I need to rotate by atan(1.414) = 54.7°.
> > >
> > > I do this with
> > > rotate(45,[1,0,0]){
> > >     rotate(54.7,[0,1,0]){
> > >         color("cyan") cube(10,center=true);
> > >     }
> > > }
> > > and the result is
> > > <http://forum.openscad.org/file/t2335/cube2.png>
> > >
> > > What am I doing wrong?
> > >
> > > Is there a simple way to get a cube at the origin with it's corners on
> the
> > > axes?
> > >
> > > Mike.
> > >
> > >
> > >
> > > --
> > > Sent from: http://forum.openscad.org/
> > >
> > > _______________________________________________
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> > >
>
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>
>
> --
> ** R.E.Wolff at BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 **
> **    Delftechpark 26 2628 XH  Delft, The Netherlands. KVK: 27239233    **
> *-- BitWizard writes Linux device drivers for any device you may have! --*
> The plan was simple, like my brother-in-law Phil. But unlike
> Phil, this plan just might work.
>
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