RealFlow Wisdom

RealFlow blog: Tips, Technics and Scripting.

How to know you are using the correct resolution?

Maybe this post can be simple for the most advance users but could help to newbies to understand the importance of the resolution parameter used in the emitters. You can detect the lack of resolution in your fluids if you see a thin layer of particles stuck to the side of the objects.  Have a look to next videos.

This video shows an emitter with resolution set to 1.0, you can observe a layer of particles stuck to the side of the glass.

Next video shows that increasing the resolution to 10.0 you will rid of the layer, but if you look carefully you see there is still a layer on the top sides of the fluid.

In next video you can see the best results but maybe it is not needed to increase so much the resolution up to 50.0 and a value of 25.0 or 35.0 would be enough for this simulation.  Obviously you can get better results with a better accuracy simulation but much more time to compute it will be needed.

July 13, 2010 - Posted by | Particle Base Fluids, Tips | , ,


  1. Thanks! I was having just this issue on a project I’ve been working on.

    Comment by Brian Looney | July 14, 2010 | Reply

  2. I would like that this should be a minimum resolution for proper fluid behavior but of course one should / could increase res until desired level of detail is achieved.

    Most common problem is that in nature we don’t see much of detail (even when recorded, we see “motion blur” on quick moving fluids) and this is the way we should render it and watch it to check if we have enough details for our final look.
    Of course we could watch slow motion videos, (widely available over net) but it’s only when you need to achieve also a slow-motion effect. When playing normally (25 or 30 fps) we should not see same amount of detail.

    Motion blur is very important here.

    Comment by tmdag | July 17, 2010 | Reply

    • Thanks Albert! That´s totally right. The final resolution will always determined by the look in the render. This could be an aproximation to get a good start.

      Comment by jalixko | July 21, 2010 | Reply

  3. Hi,

    One thing, What happens with the particle mass?? I´m working in a project that the particles of the fluid interact with objects and when I rise the resolution of the emmiter the particle mass decrease and the particles interact in a diferent way with objects. How can I compensate this??

    Thank you.

    Comment by lossesos | August 17, 2010 | Reply

  4. Good question!! If you revise the basic physics, this is the density, you will find the density is directly connected to mass, for that reason the particle mass decrease. This is the normal behavior, you get a diferent bahaviour because you get more accuracy with more resolution. But if you want to keep the same particle mass you only need to increase the density in the same way as resolution. Could you send any comparisson?

    Comment by jalixko | August 17, 2010 | Reply

    • Sorry,

      I deleted all previous sims.I solve it increasing density as you said.

      Comment by lossesos | August 18, 2010 | Reply

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