Hi RD, you can keep your units in mm instead of cm for this case but what is it that you're trying to gain by having the grid displayed in 1mm blocks? it's just too tiny in relation to your full model size.

If you want the grid to be spread out over a larger area then the simplest way to do it is to make the grid size to be larger, like set grid size to 10mm. You can leave everything else including the actual grid snap to 1mm .

That way you'll have a few hundred grid lines being displayed instead of a few thousand lines being displayed.

- Michael