Jholsenback: 1 revision: Reference Migration Initial Load

2012-03-15T19:06:04Z

1 revision: Reference Migration Initial Load

Jholsenback: 1 revision: Initial Load (TF)

2012-03-11T22:27:10Z

1 revision: Initial Load (TF)

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[[Category:Objects]]
[[Category:Constructive Solid Geometry]]
{{#indexentry:CSG, difference}}
{{#indexentry:difference, keyword}}
{{#indexentry:keyword, difference}}
The CSG <code>difference</code> operation takes the intersection between
the first object and the inverse of all subsequent objects. Thus only points
inside object <code>A</code> and outside object <code>B</code> belong to the
difference of both objects.

The result is a subtraction of the 2nd shape from the first shape as shown
in the figure below.

<table class="centered" width="660x" cellpadding="0" cellspacing="10">
<tr>
<td>
[[Image:RefImgDiffobj.gif|center|640px]]
</td>
</tr>
<tr>
<td>
The difference between two objects.
</td>
</tr>
</table>

The syntax is:
<pre>
DIFFERENCE:
difference {
SOLID_OBJECTS...
[OBJECT_MODIFIERS...]
}
</pre>

The component objects must have well defined inside/outside properties.
Patch objects are not allowed. 
Note: If the first object is entirely inside the subtracted objects, the difference object disappears.

Here is an example of a properly formed difference:
<pre>
difference {
box { <-1.5, -1, -1>, <0.5, 1, 1> }
cylinder { <0.5, 0, -1>, <0.5, 0, 1>, 1 }
}
</pre>

Note: Internally, POV-Ray simply adds the <code>inverse</code> keyword
to the second (and subsequent) objects and then performs an intersection.
 The
example above is equivalent to:
<pre>
intersection {
box { <-1.5, -1, -1>, <0.5, 1, 1> }
cylinder { <0.5, 0, -1>, <0.5, 0, 1>, 1 inverse }
}
</pre>

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Jholsenback: 1 revision: Reference Migration Initial Load

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