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I want to create large maps. I considered that single precision floating point has 23 bits for storing value so with millimeter precision of the map and movement 2^23 is the maximum size for each direction times 2 because it can go plus and minus direction. This is 16 kilometers if I am not wrong about it.

I started modeling so first I wanted a plane which is 9.5 kilometers in size (in both directions). Then I got the plane, then I used scrollwheel to zoom out and got some image artefact, the plane model was disappearing going low. This is maybe because of camera far clipping range, I will check this next.

But in theory can I model such a sized map in Blender? Is the distance precision in millimeters?

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    $\begingroup$ Hi :). Should be perfectly possible. The only technical size limit is 20*20*20 kilometers for a single object. blender.stackexchange.com/q/174524/78972 $\endgroup$ May 10, 2022 at 10:23
  • $\begingroup$ Just something to consider: Blender uses single precision floating point variables for coordinates. this means that while you can design locations even on scale of star systems, the precision drops as you move away from world origin. The smallest step of the floating point value from 10 is 0.0000001, so meters away from the world origin the precision is 0.1 µm. The smallest step from 5000 is 0.0005, so 5 km away from world origin the precision drops to 0.5 mm. You can work around that, however. $\endgroup$ May 10, 2022 at 19:24
  • $\begingroup$ Have the size be relative, there is no reason to follow the "real" sizes, especially since that can affect floating point precision at the extreme ends of the range. In all honesty, I actually get really irked by someone asking "can I create some model with X [insert real unit here]" because there are no real units, It only makes sense to actually have everything be proportionally accurate, that is having the scale of objects only be accurate relative to each other. $\endgroup$
    – lwswl
    May 11, 2022 at 1:54

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The artifacts you are seeing is probably z-fighting and have probably more to do with your camera's start clipping plane, make sure you increase that as well when you change your far clipping plane, putting it up by a few meters will make a big difference in the amount of z-fighting you're seeing.

Clipping distances

You definitely can make a map of that size in Blender, the precision issues are going to be a bigger deal in whatever game engine you are using since that's where the player will feel the jitter in the movement.

Distances in Blender are measured in meters by default.

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