I use splines a lot in animations (to direct objects and cameras). But since I
use version 3.7 I get the message:

Parse Warning: This rendering uses the following experimental feature(s):
spline. The design and implementation of these features is likely to change in
future versions of POV-Ray. Backward compatibility with the current
implementation is not guaranteed.

Does this mean that there will be no more possibilities to use splines, or that
only the syntax will change?

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On 03/23/2013 12:12 PM, nimda wrote:
> I use splines a lot in animations (to direct objects and cameras). But since I
> use version 3.7 I get the message:
>
> Parse Warning: This rendering uses the following experimental feature(s):
> spline. The design and implementation of these features is likely to change in
> future versions of POV-Ray. Backward compatibility with the current
> implementation is not guaranteed.
>
> Does this mean that there will be no more possibilities to use splines, or that
> only the syntax will change?
>
most likely the later ...

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James Holsenback <nom### [at] nonecom> wrote:
> On 03/23/2013 12:12 PM, nimda wrote:
> > I use splines a lot in animations (to direct objects and cameras). But since I
> > use version 3.7 I get the message:
> >
> > Parse Warning: This rendering uses the following experimental feature(s):
> > spline. The design and implementation of these features is likely to change in
> > future versions of POV-Ray. Backward compatibility with the current
> > implementation is not guaranteed.
> >
> > Does this mean that there will be no more possibilities to use splines, or that
> > only the syntax will change?
> >
> most likely the later ...

I hope it is. Apart from moving objects I also use splines to trigger events:

#declare TimeLine =
  spline {
    linear_spline
    0.00, < .9, .9, 0>,
    0.25, < 0,  .8, 0>,
    0.50, < 0,   0, 1>,
    1.00, < 0,   0, 1>
  } //-------------------

object {
    FoxPosition(0, TimeLine(clck).x, TimeLine(clck).y)
    rotate y*90 translate <0,-.25,-.3>
    }
#if  (TimeLine(clck).z=1)
text { ttf "arial.ttf", "?", 0.2, 0.0
       texture{ pigment{ color rgb<1,1,1>*1.3 }
              //normal { bumps 0.5  scale 0.01 }
                finish { phong 0.1 }
              } // end of texture
       no_shadow
       scale .1
      translate <-.025 ,.1 ,-.75>
      }
#end

Between time = 0 and 0.25 the fox opens its left eye and start opening its right
eye. Between 0.25 and 1 the right eye opens completely. At time = 0.5 a question
mark appears above it's head.

I hope that in a future implementation it will be possible to use more than the
x, y and z components so it can be used to make complex time tables.

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nimda wrote:

> Between time = 0 and 0.25 the fox opens its left eye and start opening its right
> eye. Between 0.25 and 1 the right eye opens completely. At time = 0.5 a question
> mark appears above it's head.

this sounds like fun ;)

> I hope that in a future implementation it will be possible to use more than the
> x, y and z components so it can be used to make complex time tables.

An interesting use of splines, but implementing n-dimensional splines
for this maybe a bit overkill. It probably only makes sense with linear
splines since you need to have independent interpolation for each
timeline. But you can get the same effect using a 2d array initializer
(see 3.3.1.10.2). Then you just need one macro TIMELINE(t,n) to find
the rows before and after a given time t, and return the interpolated
value for timeline n.

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> nimda wrote:
>
> > Between time = 0 and 0.25 the fox opens its left eye and start opening its right
> > eye. Between 0.25 and 1 the right eye opens completely. At time = 0.5 a question
> > mark appears above it's head.
>
> this sounds like fun ;)
>
> > I hope that in a future implementation it will be possible to use more than the
> > x, y and z components so it can be used to make complex time tables.
>
> An interesting use of splines, but implementing n-dimensional splines
> for this maybe a bit overkill. It probably only makes sense with linear
> splines since you need to have independent interpolation for each
> timeline. But you can get the same effect using a 2d array initializer
> (see 3.3.1.10.2). Then you just need one macro TIMELINE(t,n) to find
> the rows before and after a given time t, and return the interpolated
> value for timeline n.

This seems very feasible to me. Thanks for the hint.

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"nimda" <nomail@nomail> wrote:
> Does this mean that there will be no more possibilities to use splines, or that
> only the syntax will change?

Certainly the latter.  Splines are too useful a concept, and not just for
animations.

For example, LightsysIV is a very popular 3rd party POV-Ray library that uses
splines for color processing.  It was written by Jaime Vives Piqueres, one of
the POV-Ray elites, and Ive, our resident color expert (also Philippe Debar,
whom I'm not familiar with).

Splines can be used in constructing objects, for example, an alternative to
sphere_sweep that, while less smooth, would be less prone to artifacts.

If splines disappear, there will be a user revolt.

Radiosity also gives the same warning, and it may be more illustrative of what
the warning means.  As per the warning, significant changes have been made to
radiosity from version 3.6 to 3.7.  However, no one has ever talked about
getting rid of it; indeed, this would seriously compromise the quality of the
software.

Just be prepared to edit your scene files as these features are fleshed out.

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"nimda" <nomail@nomail> wrote:
> I hope that in a future implementation it will be possible to use more than the
> x, y and z components so it can be used to make complex time tables.

I have tried splines with 4-D vectors, and it already works.  According to the
documentation, up to 5-D vectors will work.

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