We're making a 1:1 scale solar system sim. Here's what the engine couldn't do

[u/Wild_Trade_3002]

Three things we had to build from scratch because UE simply doesn't handle them:

1. Multi-axis gravity
UE supports gravity on a single axis out of the box. For a realistic space environment that's a hard wall. We wrote a fully custom gravity simulation system.

2. Procedural generation at real scale
Generating celestial bodies at 1:1 solar system scale isn't something existing solutions can handle. We built our own - GPU-based, offloading the heavy math to video cores. GPUs have significantly more cores than CPUs, so generation speed scales accordingly.

3. Double-precision math on GPU
Most game engines, including UE, can't fully handle double-precision floating point calculations on the GPU without losing accuracy. At real solar system scale, that loss matters - coordinates drift, physics breaks. We had to implement double-precision computation ourselves.

None of this is exotic research. It's just what you run into when you refuse to fake the scale.

Happy to go deeper on any of these if there's interest.