V-cut gerber format

In Eagle, the copper "polygons" are made up of many parallel overlapping traces. If the polygon's linewidth is set to something small, like 1 mil, it quickly consumes large amounts of data when converted to Gerber.

If you change the polygon's linewidth to something thicker, it will solve this problem. However, it also affects any thermals tied to the polygon, and can cause the polygon's borders to change.

If you need your current polygon settings, then I would suggest that you make a small-width, detailed polygon where it is important, and make a larger, coarse one over the rest of that layer.

I have run into this exact problem myself. The issue is that Eagle is playing a bit "fast and loose" with the formatting of the drill coordinates, and this causes Viewmate to infer the incorrect scaling. I messed around for a while before I finally wrote a short Perl script that reads in the Eagle file and writes a fresh one with a fixed number of digits for the coordinate values, which Viewmate reads correctly.

Unfortunately, that script is on a different machine, and it will be several days before I have access to that machine again. When I do, I'll add the script here. In the meantime, maybe this is enough of a clue to get you unstuck.