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.

mismatched vertices


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?

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    $\begingroup$ Hello and welcome to BSE. What you describe here does not correspond to my experience... could you upload an example file, so that some can test what you say here? Thanks. You can use this link to upload it: blend-exchange.giantcowfilms.com $\endgroup$
    – lemon
    Feb 28, 2017 at 18:24
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    $\begingroup$ Without further info my guess is your are hitting the precision limit of modelling in Blender. Every application has its own, and in 3D modelling realm everything is always rounded to a certain level, no application you use can be infinitely precise. Being a perfectionist myself I struggled with that for a while, then I started to realize, does it matter? Will you ever see that level of detail? Will those micrometer cause any issues? $\endgroup$ Feb 28, 2017 at 18:26
  • $\begingroup$ Well rotating in object mode you get the benefit of always being able to use the original alignment axis (assuming you want that) whereas applying rotation will make it permanent part of the object geometry, with no easy way to move along the original axis if you still want that. $\endgroup$ Mar 1, 2017 at 1:56

1 Answer 1


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?

enter image description here

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 ?

enter image description here

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

  • $\begingroup$ Also, your object seems to be rotated in Object Mode, making it a non orthogonal grid. If you truly wishh to make a grid-aligned sort of tiled-world, for ease of use sake it is probably better to rotate in object mode, so you can keep local coordinates constrained to the main XYZ axis $\endgroup$ Feb 28, 2017 at 22:49

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