Developer Insights #10 – Collisions

[Pixophir]

On 8/24/2021 at 7:25 PM, KSP_linux0191 said:

Two questions:

1): Why don't you use a 64-bit float point? Is that even in the unity engine, or does it not exsist? and

Ah, wasn't aware that KSP 2 will still have the downsized planets and thus specifically adapted physics and gravity. Bummer.

The 64bit problem is essentially a platform question and what to do on the CPU and what on the GPU. No problem on desktop computers (and even most mobiles) but still essentially prohibitive on graphics cards. Both Nvidia and AMD limit FP64 to a fraction of the FP32 performance. For anything 64 bit wide that has to be passed into the graphics render pipeline or for computation on the GPU there would be a lot of gymnastics to perform that have serious impact on performance. If someone has tried this before, they now what I mean. It would probably be easier to do a complete software renderer with everything 64bit, at the cost of shale graphics, and a few people of the team doing nothing but engine development.

Also I don't know how flexible the Unity engine actually is.

Modern CPU's parallel capabilities are vastly underwhelmed with games, which usually need a performant main thread and some workers at the side. Games as a whole don't lend well to parallelism. One could do physics in 64bit accuracy (which would cover for instance the solar system out to Jupiter at a resolution of 1m) easily on a cpu, without performance impact simply because so many cores just hang around idle.

There was a time, before the pandemic and supply chain interruption and shortages, when AMD started with 64bit graphics cards in the consumer sector, but it'll probably take some time till we get there again, if at all. That would be a game changer (sic) for the simulation sector. But it may well be that things go the wrong way for us, with Intel planning to charge extra for CPU features.

tl,dr: Bummer that the planets are still dwarfs.

Edited June 8, 2022 by Pixophir

[Bej Kerman]

On 6/8/2022 at 11:27 PM, Pixophir said:

Ah, wasn't aware that KSP 2 will still have the downsized planets and thus specifically adapted physics and gravity. Bummer.

Weren't you?

I mean, real scale wouldn't be so much fun as time consuming.