Exploded text not seen when imported into FormZ as 3dm or dwg

Hi,
having drawn a ruler grid 2inch spacing my text 0 12 24 36 etc isnt seen in Form Z when importing as 3dm , so I explode it, yet still same thing. all but one number 84.

If I fill it with hatch it shows.

even if I try for dwg2004 solid export of that text.

yet the ruler lines are seen each time.

I also have now tried giving hatch fill solid to the numbers and still no joy.

any ideas ?

Steve