public static function fromString(string $stlFacetNormalString) : STLFacetNormal
    {
        $class = new self();

        preg_match("/facet normal +(\-*\d+\.*\d*e*\-*\+*\d*) +(\-*\d+\.*\d*e*\-*\+*\d*) +(\-*\d+\.*\d*e*\-*\+*\d*)/",
            $stlFacetNormalString, $matches);
        $class->setCoordinatesArray(array((float)$matches[1], (float)$matches[2], (float)$matches[3]));

        $lines = explode("\n", $stlFacetNormalString);
        $vertex = "";
        for ($i = 1; $i < count($lines) - 1; $i++) {
            $vertex .= $lines[$i];
        }
        $class->setVertex(STLVertex::fromString($vertex));

        return $class;
    }