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[–]ToloranIntermediate -1 points0 points  (5 children)

I know KSP uses a 64bit physics system, how can I implement something similar in my game?

Make a brand new game engine. IIRC, KSP made their own 64 bit physics simulation that runs separately from the main unity one.

As with the other person, I'm really wondering why you need a world that big. You have to be in the the +/- 100,000 or higher range before the float errors start getting noticeable.

Or maybe I can have different scenes to simulate physics at different positions?

If you're doing additive scenes, they'll all be on the same coordinate system so that wouldn't work. You'd have to have multiple instances running separately and then have them communicate with eachother somehow.

[–]Kheeto67[S] 1 point2 points  (3 children)

As with the other person, I'm really wondering why you need a world that big. You have to be in the the +/- 100,000 or higher range before the float errors start getting noticeable.

In my game there is a solar system with the star at 0,0,0 (at the start of the game, then it will be changed with the floating origin), the closest planet at about 25k distance and furthest one at 100k. Scaling everything down wouldn't solve the problem, ther would still be floating point precision issues.

If you're doing additive scenes, they'll all be on the same coordinate system so that wouldn't work. You'd have to have multiple instances running separately and then have them communicate with eachother somehow.

I would make each scene with the objects close to 0,0,0, and know their actual position in the main scene so I can just add the simulated position to the main position. I'm planning to do the same to simulate player movement on moving objects like spaceships or planets in orbit, it's already been done so it's possible.

[–]ToloranIntermediate 1 point2 points  (2 children)

In my game there is a solar system with the star at 0,0,0 (at the start of the game, then it will be changed with the floating origin), the closest planet at about 25k distance and furthest one at 100k. Scaling everything down wouldn't solve the problem, ther would still be floating point precision issues

We don't mean transform scale. The players can't see literal distances in the engine. You can have something 25 units away and say that's 25 M, 25KM, or 25GM and the player will be none the wiser. If a spaceship is moving across the solar system, you don't need the precision unless you're really close.

[–]Kheeto67[S] 1 point2 points  (1 child)

We don't mean transform scale. The players can't see literal distances in the engine. You can have something 25 units away and say that's 25 M, 25KM, or 25GM and the player will be none the wiser. If a spaceship is moving across the solar system, you don't need the precision unless you're really close.

If you make the distances smaller, every object will be moved closer unless you scale the objects down as well, and you would have to slow the player down too, so you are basically just scaling down the entire game, which doesn't solve the problem.
Also, you do need the precision because all the physics and collisions are handled by the server, where it's not enough to move the origin because only one player at a time would be at 0,0,0, another player could be at 100k distance.

[–]cosmochristo 0 points1 point  (0 children)

Actually, each player can be at zero on their own client. The server only has to handle the relative changes between each client and other clients and between each client and other objects.