POV-Ray : Newsgroups : povray.beta-test : Strange spline behaviour Server Time
30 Jul 2024 16:26:54 EDT (-0400)
  Strange spline behaviour (Message 1 to 3 of 3)  
From: Hugo
Subject: Strange spline behaviour
Date: 12 Oct 2001 12:28:30
Message: <3bc71a2e$1@news.povray.org>
Hello again!

Well, again I don't know if this has been addressed already.. But why is it,
that this spline comes out different every second time I render it? And it
doesn't behave as good as in MegaPOV.. Either the effect of the spline
keywords have deliberately changed ... or it's a bug.

Regards,
Hugo


// -- begin
#version 3.5;

camera { right -1.33*x up 1*y direction 1*z location <0,0,8> look_at 0 angle
48 }
light_source { <-25,25,35> color rgb 1.5 }

#declare Rounding_One = spline { cubic_spline
    0,<0,-1.5,0>
  .11,<0,-1.33,0>
  .25,<0,-1.25,0>
      .33,<0,-1,0>
      .66,<1,1,0>
      .75,<1,1.25,0>
      .88,<1,1.33,0>
        1,<1,1.5,0> }

#declare ctr=0;
#while (ctr<1)
 sphere { Rounding_One(ctr),.125 pigment { rgb 1 } }
 #declare ctr=ctr+.001;
 #end

cylinder { 2*y,1.5*y,.125 translate 1*x pigment { rgb 1 } }
// --- end


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From: Mark Wagner
Subject: Re: Strange spline behaviour
Date: 12 Oct 2001 23:21:17
Message: <3bc7b32d@news.povray.org>
Hugo wrote in message <3bc71a2e$1@news.povray.org>...
>
>Well, again I don't know if this has been addressed already.. But why is
it,
>that this spline comes out different every second time I render it?

I can't duplicate this problem with either 3.5 beta or my development
version.

> And it
>doesn't behave as good as in MegaPOV.. Either the effect of the spline
>keywords have deliberately changed ... or it's a bug.


What do you mean by "doesn't behave as good"?  The only change between
MegaPOV and POV 3.5 splines is that the 3.5 splines are true cubic splines,
rather than the fakes used in MegaPOV.

--
Mark


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From: Hugo
Subject: Re: Strange spline behaviour
Date: 13 Oct 2001 07:44:14
Message: <3bc8290e$1@news.povray.org>
Ok,

> I can't duplicate this problem with either 3.5 beta or my development
> version.

I see that Ingo and a few others are discussing this, so I am not the only
one. Clearly this problem exsist, however it is a periodic bug that comes to
the surface from time to time - for unknown reasons, and stays until you
restart Pov3.5.

> What do you mean by "doesn't behave as good"?  The only change between
> MegaPOV and POV 3.5 splines is that the 3.5 splines are true cubic
splines,
> rather than the fakes used in MegaPOV.

When the above mentioned bug comes to the surface, the spline look wrong..
It doesn't end or start at the given coordinates. That was what I meant.
Good luck in finding this bug.

Hugo


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