# GPU\_SIMULATION and array command

**URL:** <https://forums.unrealengine.com/t/gpu-simulation-and-array-command/1166335>\
**Category:** FX\
**Tags:** gpu-particles, unreal-engine, UE5, question\
**Created:** [May 15, 2023, 10:37am UTC](https://forums.unrealengine.com/t/gpu-simulation-and-array-command/1166335 "2023-05-15T10:37:36Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![GolovlevVlad](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@GolovlevVlad](https://forums.unrealengine.com/u/GolovlevVlad)\
**Post date:** [May 15, 2023, 10:37am UTC](https://forums.unrealengine.com/t/gpu-simulation-and-array-command/1166335/1 "2023-05-15T10:37:36Z")

</div>

Hi all! why is this code not working? At the same time, if you remove “#if GPU\_SIMULATION”, then everything works. The emitter runs on the GPU, that is, sim target = GPUCompute Sim is set in the property. Or is working with arrays in niagara available only on the CPU?

 ![dc8f17b4bca9de42d69329a369939566cd6161d5](https://d3kjluh73b9h9o.cloudfront.net/original/4X/d/c/8/dc8f17b4bca9de42d69329a369939566cd6161d5.png)