I have tried a couple of different slicers (Cura, Simplify3D) and get the same issue; when laying down the first layer there are often little holes at the intersection of the crosses in the grid. Inspecting the sliced layers, the reason for this is clear, the tool path avoids these regions.
I suppose the reason is that the slicer assumes the extruded plastic laid all four sides of the intersection will extend far enough to meet in the middle, but this is not often the case. It is only achieved by increasing the z offset a little, smashing the first layer, but then I end up with the grid being thicker than specified.
I have a 0.6 mm nozzle, and have set 0.333 mm layer height, 100% infill. The struts in the grid are 1.2 mm.
Any help would be greatly appreciated. Sorry if I got the wrong part of the forum.
Not the easiest way to fix it but if you create 2 models one with outer part and horizontal lines and the other just with the vertical lines put them together in simplify3d and use 2 processes toghet it will be forced to do it complete as you want it. Other option is use infill to make the grid instead of creating it in the cad software.
Sort of a workaround, maybe not what you're after . . .
Model it with the lines in one direction only, at a thickness of your printed layer height 0.333
Then model the next layer at the same layer thickness with the lines at 90 degree to the first.
Then copy the layers until you have the desired thickness overall.
It will avoid lots of line start/stops at the intersections. In theory you will have a 'lattice' sideways between the layers but in practice I think they'll join up sagged by 0.333 at the top
I haven't used sketchup so I don't know how straightforward it is as some other CAD software where its not as tricky as it sounds.