Reference:Sturm Object Modifier - Revision history

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2016-09-15T22:35:51Z

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2012-03-15T19:08:57Z

1 revision: Reference Migration Initial Load

Jholsenback: 1 revision: Initial Load (TF)

2012-03-11T22:27:16Z

1 revision: Initial Load (TF)

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[[Category:Object Modifiers]]
{{#indexentry:sturm, object modifier}}
{{#indexentry:object modifier, sturm}}
Some of POV-Ray's objects allow you to choose between a fast but
sometimes inaccurate root solver and a slower but more accurate one. This is
the case for all objects that involve the solution of a cubic or quartic
polynomial. There are analytic mathematical solutions for those polynomials
that can be used.

Lower order polynomials are trivial to solve while higher order polynomials
require iterative algorithms to solve them. One of those algorithms is the
Sturmian root solver. For example:
<pre>
blob {
threshold .65
sphere { <.5,0,0>, .8, 1 }
sphere { <-.5,0,0>,.8, 1 }
sturm
}
</pre>

The keyword may optionally be followed by a float expression which is
interpreted as a boolean value. For example <code>sturm off</code> may be
used to force it off. When the keyword is specified alone, it is the same as
<code>sturm on</code>. By default <code>sturm</code> is <code>off</code> when not specified.

The following list shows all objects for which the Sturmian root solver can
be used.
<ul>
<li>blob</li>
<li>cubic</li>
<li>lathe (only with quadratic splines)</li>
<li>poly</li>
<li>prism (only with cubic splines)</li>
<li>quartic</li>
<li>sor</li>
<li>torus</li>
</ul>

@@ Line 32: / Line 32: @@
 <li>lathe (only with quadratic splines)</li>
 <li>lemon</li>
 <li>poly</li>
 <li>prism (only with cubic splines)</li>

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