[OpenSCAD] Newbie rotation confusion.

Rogier Wolff R.E.Wolff at BitWizard.nl
Fri Sep 7 06:26:26 EDT 2018


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/
> >
> > _______________________________________________
> > OpenSCAD mailing list
> > Discuss at lists.openscad.org
> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
> >

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** R.E.Wolff at BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 **
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