FVersionedNiagaraEmitterData API
没有找到 CPU/GPU 模拟对比的官方概念文档（5.8、5.0、4.27 的 Emitter Properties 页均重定向到首页）。API 层面事实：
- SimTarget (ENiagaraSimTarget), EditAnywhere Category Emitter.
- MaxGPUParticlesSpawnPerFrame: "An override on the max number of GPU particles we expect to spawn in a single frame." EditCondition SimTarget == GPUComputeSim.
- CalculateBoundsMode (ENiagaraEmitterCalculateBoundMode) "How should we calculate bounds for the emitter"; FixedBounds when mode is Fixed.
- GPUComputeScript (protected); bNeedsPartialDepthTexture "Indicates we use the partial depth textures"; bRequiresViewUniformBuffer "Indicates that the GPU script requires the view uniform buffer".
- bGpuAlwaysRunParticleUpdateScript: "GPU scripts were incorrectly running both particle spawn & update, CPU only runs spawn when interpolated spawning is disabled."
- bDeterminism / RandomSeed; bLocalSpace; AllocationMode / PreAllocationCount.