POV-Ray : Newsgroups : povray.advanced-users : subtle behavior of Spline_Trans() macro in transforms.inc : Re: subtle behavior of Spline_Trans() macro in transforms.inc Server Time
5 Jul 2024 12:42:38 EDT (-0400)
  Re: subtle behavior of Spline_Trans() macro in transforms.inc  
From: Kenneth
Date: 22 Apr 2009 15:10:03
Message: <web.49ef6a5a987a083ff50167bc0@news.povray.org>
"scott" <sco### [at] scottcom> wrote:

>
> As a rough rule-of-thumb, if R is the minimum radius of curvature in your
> spline, and D is the minimum error acceptable (in degrees) between the
> actual direction and the calculated direction, then use a foresight length F
> of:
>
> F = R * D / 50
>
> For example, if the tightest part of your spline is similar to a circular
> arc of radius 5 units, and you want alignment accuracy to within 1 degree,
> then use a foresight length of 5 * 1 / 50 = 0.1 units.

I think *this* would make a good addition to the docs as well! Although it's a
bit technical, there are similar kinds of 'detailed explanations' to be found
in other parts of the docs, for those who want/need them. (And in fact, the
idea that Foresight is actually a 'length' and vector direction--between two
adjacent, interpolated spline points--would be good to advertise too.)

KW


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