Re: [Gnuplot-info] plot 2D circle in 3D graph

[Amir S. <ami...@gm...>]

Thank you so much  Jody, tomorrow I'll try it.

On 20 April 2011 17:22, jody <jod...@gm...> wrote:

> HI Amir
>
> if your plane equation is p*x + q*y +r*z + d = 0,
> then two orthogonal vectors in your plane are for example a=(q, -p, 0)
> and b=(p*r, q*r, -(p^2+q^2))
> Usually it is a good idea to scale those vectors to unit length
>
> Jody
>
>
> On Wed, Apr 20, 2011 at 5:13 PM, jody <jod...@gm...> wrote:
> > Hi Amir
> >
> > To display the plane you have to find its parametric description, i.e.
> > x = a1*u+b1*v+c1
> > y = a2*u+b2*v+c2
> > z = a3*u+b3*v+c3
> >
> > in other words, you have to find two vectors a=(a1, a2, a3) and b=(b1,
> b2, b3)
> > spanning your plane, as well as the offset c=(c1,c2,c3)
> >
> > then you can plot your plane like that
> >
> >  splot [u=-5:5] [v=-5:5] a1*u+b1*v+c1, a2*u+b2*v+c2, a3*u+b3*v+c3
> >
> > simple example
> >  x = u
> >  y = v
> >  z = 3
> >
> > the you plot it lie this:
> >
> >  splot [u=-5:5] [v=-5:5] u, v, 3
> >
> > Jody
> >
> >
> > On Wed, Apr 20, 2011 at 4:22 PM, Amir Sabbagh <ami...@gm...>
> wrote:
> >> Hi Jody,
> >> thank you very much for the answer, it helped a lot.
> >> is it possible to dispklay both the circle and the plane?
> >>
> >> On 20 April 2011 13:52, jody <jod...@gm...> wrote:
> >>>
> >>> Hi Amir
> >>>
> >>> Yes. For patametric curves you first have to type
> >>>
> >>>  set parametric
> >>>
> >>> next set your constants
> >>>  R=5
> >>>  d=4
> >>>  e=6
> >>>  c=15
> >>>
> >>> and then do the plotting (splot is for 3d plots)
> >>>  splot [t=0:2*pi]  d+R*cos(t), e+R*sin(t),c
> >>>
> >>> Hope this helps
> >>> Jody
> >>>
> >>> On Wed, Apr 20, 2011 at 12:28 PM, Amir Sabbagh <ami...@gm...>
> wrote:
> >>> > Thank you Jody for the tip. The problem with this option is that I
> get a
> >>> > "undefined variable: t" error when I try to splot it.
> >>> > Maybe there is a workaround for this?
> >>> >
> >>> > Amir
> >>> >
> >>> > On 20 April 2011 12:00, jody <jod...@gm...> wrote:
> >>> >>
> >>> >> Hi Amir
> >>> >>
> >>> >> You could try a parametric version of your circle:
> >>> >>  x = d+R*cos(t)
> >>> >>  y = e+R*sin(t)
> >>> >>  z = k
> >>> >>
> >>> >> This gives you a horizontal circle centered at (d,e,k)
> >>> >> For a tilted circle you would have to apply rotations
> >>> >> around the x and/or y axis.
> >>> >>
> >>> >> Jody
> >>> >>
> >>> >>
> >>> >> On Wed, Apr 20, 2011 at 11:36 AM, Amir Sabbagh <ami...@gm...>
> >>> >> wrote:
> >>> >> > Hi you all,
> >>> >> >
> >>> >> > I am trying to plot a circle and a plane with splot.
> >>> >> >
> >>> >> > I would like to have a circle at a Z=const value. I have tryed
> with
> >>> >> > ternary
> >>> >> > operation with no success.
> >>> >> >
> >>> >> >   splot a*x+b*y+c title "Plane", \
> >>> >> >   (x-d)**2 + (y-e)**2 - R**2==0? ((x-d)**2 + (y-e)**2 - R**2): 0/0
> >>> >> > with
> >>> >> > title "Circle"
> >>> >> >
> >>> >> > Can someone enlight me?
> >>> >> >
> >>> >> > Thank you
> >>> >> > Amir
> >>> >> >
> >>> >> >
> >>> >> > --
> >>> >> > **************************************************************
> >>> >> > Amir Sabbagh
> >>> >> > Il mio sito / My site: http://almucantarat.altervista.org
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> >>> >> >
> >>> >> >
> >>> >> >
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> >>> > --
> >>> > **************************************************************
> >>> > Amir Sabbagh
> >>> > Il mio sito / My site: http://almucantarat.altervista.org
> >>> > **************************************************************
> >>> >
> >>> >
> >>
> >>
> >>
> >> --
> >> **************************************************************
> >> Amir Sabbagh
> >> Il mio sito / My site: http://almucantarat.altervista.org
> >> **************************************************************
> >>
> >>
> >
>



-- 
**************************************************************
Amir Sabbagh
Il mio sito / My site: http://almucantarat.altervista.org
**************************************************************