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On Tue, 11 May 2004 21:10:13 +0200, Florian Brucker <tor### [at] torfbold com> wrote:
> So: What is the idea behind this? Will the concept of splines be changed
> to a more uniform one in POV 4.0 (yes, I did read the output on the
> message window telling me that splines are a experimental feature :)?
The idea behind it is most probably... lack of idea :-(
IIRC splines{} are basically content of patch ported to 3.5. Original patch
wasn't integrated with lathe/prism, so after including it in 3.5 it isn't
integrated as well. It's not that simple to integrate internally (considering
that splines in lathe/prism are optimized for fiding clock for given ray while
splines{} are optimized for finding vector for given clock) and since writing
spline-based lathe/prism-like meshes is pretty simple, I do not think there is
any very serious need for it. But it would be interesting to have macro or
patch to perform conversion from old lathe/prism data to most accurate spline.
> And I got another 2 questions (which are unrelated to the questions above):
> - Why isn't it possible to use bezier_spline in spline identifiers?
Because nobody made it yet ?
I have in my TODO list to add as many spline types as possible in form of
patch to source code. It is very simple (from programmer point of view of
course :-) ). Up to now I have added akima_spline, tcb_spline, and a few
x_spline variants. If you are interested in visualisations, just follow link
in my posts in thread http://news.povray.org/povray.general/31113/ or google
for details.
> - How are the clock values for the splines of lathe/prism computed? I
> guess they are chosen proportional (?) to the distance of the points, is
> this right?
They are not chosen, they are computed. If they are in range 0-1 after
computation then intersection happens for single segment (IIRC). See source of
lathe/prism.cpp for details.
ABX
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