Grid Alignment system problem in BGE I'm currently designing a modular road system for use in a game. That, of course, means a lot of by-the-grid design and so on. I've encountered a couple of problems, however and I would love it if anyone can offer any insights. 

Problem number one: Grid align is absolutely broken, for instance,
 Both vertices are 'snapped to grid', and it looks okay when you're in the 'meters' zoomed out position if you get what I mean. But as soon as you zoom in to 'milimeters' you start seeing that stuff is not aligned properly!

Part two: What happens to the grid when you start zooming in? I mean you'll see the screenshot(the one below) but the grid lines just go nuts and start multiplying. Any idea why? 

Part three: Let me explain my confusion and frustration:

1- If you think something is aligned, zoom to the micrometer level and you'll find out that you never belonged on da grid. 

2-You can't really fix it, as you can't move anything by 1 micrometer unit and 'snap to grid' (as stated in 1) doesn't align anything on the micrometer level.

Screenshot:


EDIT

Here's an example scene: 
 

Anyway I guess it may not be an issue, but I was just trying to future-proof myself before I bring everything in Unreal and realize things don't align etc- etc. :)

Edit 2:

Holy moly, that was helpful!
@3fingeredfrog -First of all thank you so much and absolutely, a mm is plenty enough! 
@Duarte Farrajota Ramos -Oh, I usually just apply rotation/scale/position when I'm finished editing, totally forgot this time. Is there a big difference, between carefully rotating everything in object mode versus applying the rot when I'm finished?
At the moment you have the scale set at 0.01. From the testing I have just done this means you can zoom in so that each grid square that you are trying to snap to is a single micro meter. Do you really need to build roads to that level of accuracy? 



Wouldn’t it be easier to leave the scale at 1.0, then the smallest grid square that can be snapped to is a millimeter?

Which perhaps would mean that you wouldn’t be hitting the rounding / precision issue that Duarte mention ?



Posted this in the Answers section because I can’t add images in Comments