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I'm trying to create a fluid simulation using Quick Liquid for a coffee pour animation. At this point I've watched 3 different tutorials but it's still not working. What am I doing wrong?

Image 1: Here's a still from the baked liquid simulation.

image 1

Image 2: I don't remember when this occurred. But while I was setting everything up, the sphere turned into the blue swirl object.

image 2

Image 3: Here are the physics settings for the domain.

image 3

Image 4: Here are the physics settings for the flow object.

image 4

Image 5: Here are the physics settings for the coffee mug.

image 5

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The fluid simulation is based on particles. When you are simulating fluid, the domain object has a particle system called "Liquid" which contains the simulated particles. In the particle system settings under Viewport Display > Color they are usually set to Velocity, i.e. the rainbow colors are dependent on how fast the particles are moving.

When you set it up and the particles "come into existence" they are probably not moving at all at first, which is why they are blue (it is not a swirl in your image, it is just a bunch of those large spheres clumped together around the flow object).

Now for the size: I cannot see any size information on your objects or of the domain's particle system, but here are two possible scenarios:

  1. The objects are really small so that the particles appear very large.

  2. You have (accidentally or intentionally) set the Size of the particles in the particle system to a large number.

A combination of both causes is possible as well. Here is a demonstration: I have two fluid domains, one is "normal" size (a default cube with 2 m edge length) and a tiny one with just 1/30 of the default size. The important thing to know about the particle size is, the Size is an absolute size in meters, it is not relative to the domain size. This is why the following things can happen:

First of all, the particles are by default set to a Size of 0.01 m (absolute size) in the particle system:

default particle size

Zooming in on the tiny domain you can see, the particles in both domains (the large one on the left side) have the same size - they just appear huge on a very small domain:

particles on small domain

But now zooming back out to the large domain. It is 30 times larger than the small domain, so if I set the Size in the particle system to 0.01 m × 30 = 0.3 m, you can see that the particles appear huge on the large domain as well:

large domain with huge particles

Which of those circumstances occurs in your case you can only find out for yourself unless you show us dimensions of your scene objects or particle system settings.

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  • $\begingroup$ Thank you for such a detailed reply to my question! Unfortunately I'm not able to add any more images to my question, so I'll do my best to share the particle data here. Under the domain particle system tab there are "268 particles listed for this frame". RENDER: Render as halo, scale .050, scale randomness 0, material is liquid domain material, nothing selected or indicated for the coordinate system, and the show emitter box is selected. VIEWPORT DISPLAY: display as rendered, color: velocity, fade distance 1.0, amount 100%, size .01, and show emitter box is selected. $\endgroup$
    – Philadelphia_Collins83
    Commented Aug 22 at 7:26
  • $\begingroup$ The dimensions of the coffee mug in my scene are as follows: X: .111m Y: .0799m Z: .0909m $\endgroup$
    – Philadelphia_Collins83
    Commented Aug 22 at 7:30
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    $\begingroup$ @Philadelphia_Collins83 Why can't you add more images? Anyway, looking at the grid in the screenshots this seems to match the coffee mug dimensions given here, but the particles compared to it seem to be rather 0.02 m in size (the size sets the radius, so I guess this because in the images they look like they have a diameter of about 0.04 m). Whatever, so the size of the mug is real-life size I suppose. The particle size is mostly an optical problem, however the Resolution Divisions on the domain are much to low with 32 for such a small mug. I would (at the very least) double them. $\endgroup$
    – Gordon Brinkmann
    Commented Aug 22 at 9:46
  • $\begingroup$ When I tried to add more images, an error message displayed indicating that I had exceeded my data limit. $\endgroup$
    – Philadelphia_Collins83
    Commented Aug 22 at 19:50
  • $\begingroup$ Should I decease the size of the particles? Also, is the low resolution divisions responsible for the particles slowly floating around in the air rather than falling down into the cup? $\endgroup$
    – Philadelphia_Collins83
    Commented Aug 22 at 19:52

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