Difference between revisions of "Documentation Talk:Tutorial Section 3"

From POV-Wiki
Jump to navigation Jump to search
m (follow up)
Line 1: Line 1:
−
<p>
 
−
First, we would like to digress a moment to talk about the difference
 
−
between a lathe and a surface of revolution object (SOR). The SOR object,
 
−
described in a separate tutorial, may seem terribly similar to the lathe at
 
−
first glance. It too declares a series of points and connects them with
 
−
curving lines and then rotates them around the y-axis. The lathe has
 
−
advantages, such as linear, quadratic, cubic and bezier spline support. </p>
 
−
<p>
 
−
Plus, the simpler mathematics used by a SOR does not allow the curve to double
 
−
back over the same y-coordinates, thus, if using a SOR, any sudden twist
 
−
which cuts back down over the same heights that the curve previously covered
 
−
will trigger an error. For example, suppose we wanted a lathe to arc up from
 
−
&lt;0,0&gt; to &lt;2,2&gt;, then to dip back down to &lt;4,0&gt;. Rotated
 
−
around the y-axis, this would produce something like a gelatin mold - a
 
−
rounded semi torus, hollow in the middle. But with the SOR, as soon as the
 
−
curve doubled back on itself in the y-direction, it would become an illegal
 
−
declaration.</p>
 
  
−
* picked up suggested changes -- [[User:Jholsenback|jholsenback]]
+
* Jim, Thanks for making the earlier update. I noticed another place in the prism part of the tutorial where we should mention the bezier spline.
 +
 
 +
* Where we today have:
 +
 
 +
=====Teaching An Old Spline New Tricks=====
 +
<p>If we followed the section on splines covered under the lathe tutorial
 +
(see the section <!--<linkto "Understanding The Concept of Splines">Understanding The Concept of Splines</linkto>--->[[Documentation:Tutorial Section 3#Understanding The Concept of Splines|Understanding The Concept of Splines]]), we know that
 +
there are two additional kinds of splines besides linear: the quadratic and
 +
the cubic spline. Sure enough, we can use these with prisms to make a more
 +
free form, smoothly curving type of prism.</p>
 +
 
 +
* I think it should read:
 +
 
 +
=====Teaching An Old Spline New Tricks=====
 +
<p>If we followed the section on splines covered under the lathe tutorial
 +
(see the section <!--<linkto "Understanding The Concept of Splines">Understanding The Concept of Splines</linkto>--->[[Documentation:Tutorial Section 3#Understanding The Concept of Splines|Understanding The Concept of Splines]]), we know that
 +
there are three additional kinds of splines besides linear: the quadratic,
 +
the cubic and the bezier spline. Sure enough, we can use these with prisms to make a more
 +
free form, smoothly curving type of prism.</p>

Revision as of 12:52, 24 May 2016

  • Jim, Thanks for making the earlier update. I noticed another place in the prism part of the tutorial where we should mention the bezier spline.
  • Where we today have:
Teaching An Old Spline New Tricks

If we followed the section on splines covered under the lathe tutorial (see the section Understanding The Concept of Splines), we know that there are two additional kinds of splines besides linear: the quadratic and the cubic spline. Sure enough, we can use these with prisms to make a more free form, smoothly curving type of prism.

  • I think it should read:
Teaching An Old Spline New Tricks

If we followed the section on splines covered under the lathe tutorial (see the section Understanding The Concept of Splines), we know that there are three additional kinds of splines besides linear: the quadratic, the cubic and the bezier spline. Sure enough, we can use these with prisms to make a more free form, smoothly curving type of prism.

Retrieved from "https://wiki.povray.org/content?title=Documentation_Talk:Tutorial_Section_3&oldid=8518"