  The next free index or -1 it the index is already occupied
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<td class="detailHeaderName">setVertex</td><td class="detailHeaderParens">()</td><td class="detailHeaderType">method</td><td class="detailHeaderRule">&nbsp;</td>
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<code>public function setVertex(p_nVertexID:int, p_nX:Number, p_nY:Number, p_nZ:Number):int</code><p>
   Adds new point at th