How Do I Make Really Large Objects

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Sietseq

I am working on simulating the elevations of the earth and I would also like to have everything to scale. From a bit of research I had done I found out that at really long distances floating point values become less precise and the collisions get messy. How could I prevent this?

cybereality

Scale is relative. An apple would look like the size of the Earth, if you held it close enough to your face.

Calinou

To simulate real world-scale physics at an Earth scale, you'd need support for double-precision physics, which is not implemented in Godot yet.

Sietseq

@Calinou said: To simulate real world-scale physics at an Earth scale, you'd need support for double-precision physics, which is not implemented in Godot yet.

Thanks I’ll look into that issue a little bit more. Origin shifting might be what I need.

dotted

You best strategy to simulate it would be use some form of level of detail.

Only items within a radius are 'at-scale', items further away are rendered with a cruder level of detail and made to look like off in the distance with some parallax/skybox trickery.

cybereality

But there is no scale to a computer. A unit can be anything. 1 unit in a 3D engine is typically 1 meter, but it's essentially arbitrary and can be anything you want. It could be 1 inch, or it could be 1 light year. It's all the same.

Just to give you an idea, I once coded a planetary simulation in Maya a long time ago in art school. I inputted all the planets and the sun, with their actual diameter, with the actual orbit and distance, with the real values. And it was with Melscript, so it they also rotated and orbited with physical movement. After a few hours of setting that all up, I pressed play and I saw nothing. It was a blank screen. I thought I had made an error, but I did not. Everything was working. It's just that space is so huge that you cannot even see it on a computer. I had to fudge things to make it even visible, like making planets 1,000x their real size, and making the orbits 1,000x smaller, and so on. It still looked okay in the end, but of course it was not scientifically accurate.

The point of that story is that there is no reason to make things at actual scale, because in reality there is no scale. The units in a computer are completely arbitrary, and limited as well. Floating point numbers cannot represent astronomical distances accurately. And, even if they could, there would be no advantage. As I said, 1 unit can be 1 millimeter, 1 meter, 1 kilometer, or 1 light year, and it would be all the same to the computer.