I've not quite grasped how the grid works (it helps a
lot!), but I'm drawing
some schematics and I need millimetric precision
(literally), so I need each
square to be precisely 1mm2 and the nodes to snap to
them... Now the
"problem" I have is that I don't quite understand what the
"adjust distance"
attribute of the grid does and to what value set that. Any
help will be
appreciated.
I've recently been using Inkscape for schematics / block diagrams, which involved a lot of grid work.
It sounds like you are referring to the "Snap distance" field on the "Grid" tab of the Document Preferences. As far as I have found, this value is the maximum distance the cursor must be from a grid point before it will snap there.
e.g. if you have a 1x1mm grid, and snap distance is set to 0.25mm, then if you have the cursor in the centre of that grid square, it will not snap anywhere.
To make sure the cursor will always snap to the nearest grid point, snap distance should be at half of the grid spacing value. (It doesn't seem to make any difference if it is larger, so I just set all three values to the same).
Also, for schematic work, I have found that it is best to turn off the "Snap bounding boxes to grid" option, because with this on, horizontal and vertical lines will snap in three ways: first one edge will snap to the grid, then its centre line, and then the other edge.
Ken