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Mantaflow - liquid particles show up in organized unrealistic structure
Closed, ResolvedPublicBUG


System Information
Operating system: Windows 10 Home, Version 10.0.18363 Build 18363

Graphics card: ASUS R9 290X DirectCU II OC

Blender Version
Broken: V2.82 Beta, 3ba5461af0c8, 2020-02-01,

Short description of error

  1. In this attached scene a cube emits a water jet while it is moving in the Y direction in stationary water close to its surface, simulating a primitive water propulsion. I tried to do different settings for the fluid particles but the particles always show up in an organized 3D structure making it look very unrealistic as the pattern is very noticeable from nearly any direction. I gave the water particles red color to make the pattern a lot more visible.
  1. I also noticed that if I change the emitter cube initial velocity to a higher value than the previous one was, then I need to change the simulation speed to a lower value to get continuous jet of liquid flow, otherwise it seems like the fluid is pulsing. The bigger the velocity increase the bigger the gaps between the pulses.
  1. The third thing that I noticed, if the emitting cube size is under 0.15 for all 3 axis then it no longer emits liquid. Initially I tried it with 0.1 in all 3 axis and did not emit fluid.

Exact steps for others to reproduce the error

  1. To test the particle structure bake the fluid parts and render or even just deactivate the fluid and the mesh of the domain and view the fluid particles only rotating the view to examine the particle structure.
  1. For breaking the stream of fluid change the Y direction initial velocity to about 2 and bake, examine fluid flow pattern.
  1. Change the emitting cube size to 0.1 or smaller to all axis and bake.

Event Timeline

Andrew Sprok (sprad001) renamed this task from Mantaflow - liquid particles show up in organized structure to Mantaflow - liquid particles show up in organized unrealistic structure.Feb 4 2020, 4:59 AM

I tested it again with the latest daily build f51286cb8cc8, 2020-02-04 and it is still the same. I wanted to make sure that I did not miss some fixes or updates. The red bits in the water are the particles of course, for better observation.

I can confirm the regular distribution of the particles, which is impossible in the real world, but I can't say if this is an error in the settings, a limitation of the resolution or something else ...
@Sebastián Barschkis (sebbas)?

Sebastián Barschkis (sebbas) changed the task status from Needs Triage to Confirmed.Feb 7 2020, 12:30 AM
Jacques Lucke (JacquesLucke) changed the subtype of this task from "Report" to "Bug".Mar 27 2020, 11:12 AM

Issue should be resolved now! Render for frame 75 came out like this: