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**SPLINE BASED RIVERS PERFORMANCE ISSUE**

Set TopicsSET TOPICAug 28, 2026Original source

On medium and low end video cards, we might experience extreme performance drop on the Water_Sparse_River Level.
We can completely eliminate the issue by adjusting a bool flag:

  1. Open Level: /Content /FluidNinjaLive /Levels /Water_Sparse_River.umap
  2. Select Actor: NinjaLive_River
  3. At the Actor Details Panel, select NinjaLiveComponent
  4. At the Component Details Panel, look up User Parameters
  5. Locate the Spline Data Interface at DebugOnly /InputFields /SplineFields /Spline
  6. Notice the UseLUT bool flag and the associated value NumLUTSteps
  7. Set UseLUT = FALSE

Short explanation:

  • ninja is sampling the elevation (world space Z pos) of the river-splines
  • the quaility of the sampled height-data mignt not be satisfactory (quantized to discrete values)
  • the quaility of the sampled height-data could be improved by using the optional UseLUT feature
  • the feature seems to impact performance on low-end video cards (confirmed: GTX1070, RTX 3050)
  • the feature seems to be neutral on medium and high performance video cards (confirmed: RTX 2080, RTX 3080)