Gridded groundplane
See also Article Groundplane
Groundplane as grid
Find it in TARGET 3001! by the icons 
and 
or in Layoutmenu Actions / Generate Ground Plane.
This can be done by the second section of the "Groundplane Assistant" dialog:
Using this function should be the very last step during the layout process because deleting the GND-signal from Layer 2=copper bottom, will delete the grid as well as the routed GND-signal. Also the "Check Project" Function will not work because TARGET 3001! needs to check all points of the grid against the minimum spacing set. This will take a huge calculating effort and thus take too much time.
After using this function the Layout as above may look like this:
Deleting a gridded groundplane
For deletion of the gridded groundplane please use section 3 of the groundplane assistant: "Retrieve ground plane" which will create the solid status again.