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I have an issue I seem to keep coming across with the fluid simulation; I seem to be generating a strange 'ladder effect' where the fluid spreads out regular intervals as shown in the image below.

The test scene consists of an inflow onto a surface that falls away vertically to give the fluid something to flow down.

I have tried increasing resolution (to about 200), but I just achieve a higher quality ladder effect.

I wanted the scale to be 0.25m but I tried 5m and get a very similar effect.

This is something related to slip, if I make both the fluid and surface free slip i avoid the effect, as i re-introduce partial slip the ladder re-emerges.

Is this effect expected behaviour?, is it a commonly experienced phenomena?

Any guidance/views appreciated

Thanks

Effect

Side view

enter image description here

Animated ... https://i.imgur.com/Rv1COrd.gifv

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  • $\begingroup$ This is an old question. It would be interesting to know if the same can be replicated in the latest Blender version. $\endgroup$ Commented Oct 26, 2021 at 23:13

2 Answers 2

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This by all means is not common-it's probably a mistake in your domain settings. Check back at your bake location, your viscosity settings, and your particle settings for the fluid.

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  • $\begingroup$ Try re-baking in a new and empty file. $\endgroup$ Commented Jan 6, 2020 at 0:33
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This actually seems to be due to how the obstacle is interacting with the granularity (blockiness) of the domain. By default, any obstacle is mapped into the domain as entire cells. For any diagonal surface (such as the ramp in the image) this will result in a series of "steps" and the liquid will catch on those steps resulting in the ladder effect.

In current Blender versions there is a Fractional Obstacles option. Enabling this maps any obstacles to allow them to effectively smooth out the obstacle boundary and this can usually remove (or at least significantly reduce) any "stepping" as the liquid flows over the surface.

Fractional Obstacles option

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