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Comment by tezza | Hacker News Reader

“Large World Coordinates (LWC)” - fantastic.

My projects use Unity and any time the camera gets 1800m from the world (0,0,0) the camera begins to shake. By 2000m the shake is too violent to use.

So you have to reset the coordinates by a hack if you want a world scale 1:1 map

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I just created a new scene in Unity 2020.3.5 and terrain going out to 6000 and a simple camera fly-script to fly around and it all looks good to me - no shaking.

Using 32-bit floating point you'll have 0.1 accuracy up to 100000 at least.

Edit - I just realized 10cm accuracy is not great (and that I'm talking to myself) so I tested with 0.001 and that's stable up to 9000.

I've been working with Unity with the intention of making a large open world, and so this was one of the things I deliberately experimented with and tried to quantify. I found I had to be several orders of magnitude farther from the origin to notice stuff like that, and frankly I was a little disappointed that it was so hard to reproduce. Is there a sample project or description you could share that would help people observe that? I would not be surprised if certain circumstances other than purely distance make it worse. For example, when I traveled large distances solely on the world X axis, I saw my meshes quiver only when the camera was also aligned on/orthogonal to the X axis (don't remember which one exactly.)

Ue4 used to rely on the world origin shifting hack too. But this has significant problems, especially in multiplayer.

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