"Pablo" <Pab### [at] gmailcom> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > "Pablo" <Pab### [at] gmailcom> wrote:
> >
> > > Hey Bald Eagle, I tried doing the way you said but i only could to make a
> > > isosurface sin sphere and how its name says, its a sphere but I need a kind of
> > > water drop. Wich funcion could I use with the sin to make this shape? Not sure
> > > if im explaining well
> >
> > Is this close enough to what you need?
> >
> >
http://news.povray.org/povray.binaries.images/thread/%3Cweb.5a31dcc89a8d03875cafe28e0%40news.povray.org%3E/
> >
> > First I defined a "sine sphere" - just like I assume you've accomplished, but as
> > a function.
> >
> > Next I made an isosurface using that function, but replaced y with and equation
> > to non-linearly scale it.
> >
> > Then I stretched it by scaling <1, n, 1>
> >
> > Then i just made a leg with a sphere sweep, and used it 3 times, rotating +120
> > deg for the next two.
> >
> > Hope that helps - post your results (and code) in the binary images thread!
> >
> > Good luck!
>
> Wow, that's exactly what I want to do! But I don't know what equation to
> non-linearly you have put instead of the y on the "sine sphere". That's the
> point for me. So it's this function:
>
> sqrt( x*x + y*y + z*z ) - 0.9
>             + sin( 12*atan2(x, z) )*0.051
>
> (isn't it?) but on both y's that appear on the sqrt what should I replace for?
> Thanks for all the attention. (I haven't seen the work you done seting the
> product until today, i'm new on this web site. I'm so thankful, seriusly)

Oups, sorry I thought I haven't sent the message but it was the server that it
was not refreshed. I am trying with yout help, i will post the news. Thanks
again for the attention

Post a reply to this message

Hi Alain,

I gave that a whirl, and needed to modify it a bit to get it to work.

Not sure if I'm getting the same shape as you're suggesting.



#include "functions.inc"

#declare F_Ribs =
function {
 pattern {
  radial
  frequency 10 sine_wave
 }
}

#declare Central = isosurface {
 function {f_sphere (x*(y/2+1.00001), y, z*(y/2+1.00001), 1)
 + F_Ribs (x*(y/2+1.000011), 0, z*(y/2+1.000011)) -0.3
 }
 threshold 0
 accuracy 0.0001
 max_gradient 145
 contained_by {box {<-1,-1,-1>*2, < 1, 1, 1>*2}}
 scale <1, -3, 1>
}

Post a reply to this message

"Bald Eagle" <cre### [at] netscapenet> wrote:
> Hi Alain,
>
> I gave that a whirl, and needed to modify it a bit to get it to work.
>
> Not sure if I'm getting the same shape as you're suggesting.
>
>
>
> #include "functions.inc"
>
> #declare F_Ribs =
> function {
>  pattern {
>   radial
>   frequency 10 sine_wave
>  }
> }
>
> #declare Central = isosurface {
>  function {f_sphere (x*(y/2+1.00001), y, z*(y/2+1.00001), 1)
>  + F_Ribs (x*(y/2+1.000011), 0, z*(y/2+1.000011)) -0.3
>  }
>  threshold 0
>  accuracy 0.0001
>  max_gradient 145
>  contained_by {box {<-1,-1,-1>*2, < 1, 1, 1>*2}}
>  scale <1, -3, 1>
> }

I tried too with the way you propose, Alain, but I have to say that I see it
more difficult so I decided to continue the Bald Eagle's one. I whink I almost
have it, the have the central part but now, my issue (what I thought that would
be the easiest part)is the legs: I tried to do as a sphere sweep with 4 spheres
that I calculated with a b_spline or cubic but the result it gave me hasn't no
sense because it started and ended in someplace i haven't understand so i have
decided to put a linear spline temporary until I have the correct texture and
solve the problem with the sphere sweep. So I think I have the most work done
(thank of you, Alain and Bald Eagle <3!haha)I am postings the resultsi have by
now but I will post the final result when I will have it

Post a reply to this message

"Pablo" <Pab### [at] gmailcom> wrote:
I tried to do as a sphere sweep with 4 spheres
> that I calculated with a b_spline or cubic but the result it gave me hasn't no
> sense because it started and ended in someplace i haven't understand so i have
> decided to put a linear spline temporary until I have the correct texture and
> solve the problem with the sphere sweep.


You need to remember that those types of splines need extra points which don't
visibly show up in the sphere sweep.

hit F1 and look up the cubic_spline tutorial in the documentation.

Just add an extra point to the beginning and end (copy the start and finish
points, maybe shift them slightly) and that ought to get you started.

I often use VISO to design such shapes, but you can probably use any graphics
program that will give you the pixel location of the mouse pointer, and there is
also

https://agalena.nfshost.com/b1/software/epspline-prism-and-lathe-editor/

which you might find useful in the future.

Post a reply to this message

Le 17-12-25 à 19:47, Pablo a écrit :

> I tried too with the way you propose, Alain, but I have to say that I see it
> more difficult so I decided to continue the Bald Eagle's one. I whink I almost
> have it, the have the central part but now, my issue (what I thought that would
> be the easiest part)is the legs: I tried to do as a sphere sweep with 4 spheres
> that I calculated with a b_spline or cubic but the result it gave me hasn't no
> sense because it started and ended in someplace i haven't understand so i have
> decided to put a linear spline temporary until I have the correct texture and
> solve the problem with the sphere sweep. So I think I have the most work done
> (thank of you, Alain and Bald Eagle <3!haha)I am postings the resultsi have by
> now but I will post the final result when I will have it


A cubic_spline need to start and end with control points. Those points 
are not part of the visible spline. The part that you see start with the 
second point and end with the second to last point.
If you want a sharp bend, then, you need 3 points for that bend : The 
first in line with the segment going into the bend, then one at about 
the center of the bend, then one in line with the segment going away 
from the bend.

In your case, that mean a sphere_sweep with 7 or 8 points as follow :
1) start control point
2) effective start of the spline (you have it)
3) start of the sharp bend
4) middle of the sharp bend (you have it)
5) end of the sharp bend
6?) (optional) middle point of the long segment (you have it)
6 or 7) effective end of the spline (you have it)
7 or 8) end control point

Post a reply to this message