This problem looks like the following parameters are not defined correctly. The correct parameter is Engine_Emitter_NumParticles.
Engine_Emitter_NumParticles and PREV_Engine_Emitter_NumParticles


SHADER_PARAMETER(int32, Engine_Emitter_NumParticle)
SHADER_PARAMETER(int32, PREV_Engine_Emitter_NumParticle) 

Changing to the following will work correctly.

SHADER_PARAMETER(int32, Engine_Emitter_NumParticles)
SHADER_PARAMETER(int32, PREV_Engine_Emitter_NumParticles) 

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Steps to Reproduce
  1. Create a Niagara System that Gets Engine.Emitter.NumParticles.
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    Below is a project to reproduce.
  2. Check the values in the Attribute Spreadsheet.
    0 is output with GPU Compute Sim.
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    For CPU Sim it can get the correct value.
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ComponentUE - Niagara
Affects Versions5.2
Target Fix5.4
Fix Commit28359800
Main Commit28359812
CreatedJul 27, 2023
ResolvedSep 29, 2023
UpdatedOct 13, 2023
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