Looking to draw a grid based map and wondering if there's an easy to slap a grid on the canvas. Note that I'm not just looking for a guide grid, I need actual squares to be appearing on the finished piece, I also don't want the entire page covered with them, only certain areas.
I'm thinking it would be possible with the grid brush engine, but I'm not sure how. Any help would be appreciated.
Thanks

I'm not sure if I understood your question correctly (sorry for that), but there is a cross-hatch brush engine with a few brushes on it, they have plenty of options on the brush settings window, you can change angles, amount of lines, thickness, etc. some will create a grid-like pattern, and doesn't matter where you place the brush, pattern will not break. Again, not sure if that was close to what you where looking for : )

Create a new document with the size you want the grid space to be (only one layer)
Name the layer as "map grid" or anything you like.
Draw one vertical and one horizontal line in full black color. Line must be the width of the desired grid line width.
Click the "Fill Pattern" button on the top toolbar (the second button).
Click the "Custom Pattern" tab.
Press the "Update" button.
Press the "Add to Predefined Patterns" button.
Select one default brush from the pixel engine.
Open the "Edit Brush Settings" dialog.
Mark the "Pattern" checkbox.
Select the "Pattern" settings, look for the name you give to the layer and select that. (look at the bottom first)
Set the scale to 1.00 and the texturing mode to subtract.
Click away from the dialog and select the color you want.
Create your map document and happily draw your map grid.
Better to give a name and save that brush preset for future use.

Thanks folks!