$re = '/vertex.+\s[0-9\.]*[1-9][0-9\.]*$/m';
$str = 'facet normal -1.000000 0.000000 0.000000
outer loop
vertex 26.000000 6.000000 0.000000
vertex 26.000000 6.000000 -1.000000
vertex 26.000000 7.000000 1.000000
endloop
endfacet
facet normal -1.000000 0.000000 0.000000
outer loop
vertex 26.000000 6.000000 0.000000
vertex 26.000000 7.000000 1.000000
vertex 26.000000 7.000000 0.000000
endloop
endfacet
facet normal 0.000000 1.000000 0.000000
outer loop
vertex 26.000000 7.000000 0.000100
vertex 26.000000 7.000000 1.000000
vertex 27.000000 7.000000 1.000000
endloop
endfacet
endsolid ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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