$re = '/(".[>].*?")|<i3dMapping id=(?P<name>".*?") node=(".[>].*?")/m';
$str = '<movingPart index="0>8|1|3" referencePoint="0>8|1|0|4" referenceFrame="0>" scaleZ="true"/>
bla
bla
<i3dMapping id="KroneComprimaV180XC" node="0>" />
<i3dMapping id="novoGripPart2_fixPoint" node="0>8|1|0|4" />
<i3dMapping id="novoGrip_part2" node="0>8|1|3" />';
$subst = "\k'name'";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php