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I'm involved in a project to do with ink animation and experimentation. I found this incredible piece of animation:

Chinese Ink Style Animation

I originally thought this was some sort of After Effects compositing (is it even possible in AE?!), but found out that this particular animation was created in 3DS Max with Krakatoa and FumeFX. I'm just wonder if a similar effect is doable with Blender's smoke simulator.

There are various YouTube videos that have pretty decent results of ink renders from Blender, but I can't seem to find anything of a similar sort of movement animation. Just blobs floating around!
The closest thing I found was this animation of a

Rigged Character Using Blender Smoke Sim

but again I can't seem to replicate this. The smoke just doesn't seem to follow my character's animation.
Any help with this would be greatly appreciated.
Thanks.

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    $\begingroup$ This will take tons of computing power, absolutely insane. This is a very difficult effect to achieve well, and the number of particles necessary for a good result will kill your machine unless you own an animation studio, in which case you shouldn't be asking us for advice . . . It is theoretically possible with Blender however $\endgroup$ – VRM Feb 5 '15 at 20:00
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    $\begingroup$ Gottfried Hofmann created an inkdrop tutorial a while ago Using a smoke generator and turbulence: blenderdiplom.com/en/tutorials/… A modified version of the file can be found here: blenderillusionist.blogspot.ca/p/free-stuff.html $\endgroup$ – cegaton Feb 6 '15 at 4:30
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    $\begingroup$ I am working on a solution that doesn't use smoke sim, I will see how it turns out. $\endgroup$ – PGmath Feb 8 '15 at 18:59
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    $\begingroup$ Is there a particular reason why you want to use BI, or would cycles work as well? $\endgroup$ – PGmath Feb 8 '15 at 19:03
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    $\begingroup$ @JacobW.E I am attempting to use a combination of volume scatter, abortion, and emission controlled by a mix of procedural textures. So far it looks decent but I am trying to get rid of the sharp endings around the edges of the mesh and make it look more wispy. I may just post what I have so far and continue working on it though. I am not on my normal computer at the moment so I can't do it right now though. $\endgroup$ – PGmath Feb 10 '15 at 15:23
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If I understand correctly, your question is essentially asking how to emit smoke from a rigged and animated character.

This should work just fine, as long as the smoke modifier is after the armature modifier on the character mesh:

enter image description here

Example (click for a smoother video):

I found using the mesh directly as the smoke emitter provided a smoother, less lumpy result without requiring huge numbers of particles.

Smoke settings

All these settings are just stylizations on my part, they are not supposed to look like real ink in water :P

I used a fairly high resolution domain with only 1 high resolution subdivision, dissolve (though perhaps I made it dissolve a little on the fast side), and low vorticity:

enter image description here

For the emitter I used subframes and enabled initial velocity so that the smoke inherits the velocity of the part of the mesh it's emitted from (in the example render the smoke is actually "flung" by the mesh twice as fast as it technically should be, but I rather liked the effect). I also used a negative temperature difference so that the smoke drifts down over time, however I think I might have over done it a bit (the smoke falls a little fast for my taste).

enter image description here

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    $\begingroup$ One figure is worth thousand words. Nice shot gandalf3. :) $\endgroup$ – Leon Cheung Feb 11 '15 at 3:26
  • $\begingroup$ This looks amazing. I'm gonna learn how to do this. $\endgroup$ – luigi Feb 11 '15 at 3:55
  • $\begingroup$ Would you mind posting a screen-shot of the physics properties for this? Absolutely amazing! $\endgroup$ – Scalia Feb 11 '15 at 4:16
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    $\begingroup$ @Bithur it looks more inky than smokey to me. Your impression is caused by the fast gif playback..imagine it slower and you have ink..The temp diff should be higher though so it doenst fall that fast but that does not change things.. $\endgroup$ – Jaroslav Jerryno Novotny Feb 11 '15 at 12:50
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    $\begingroup$ @AWildRolandiXor Suzink, the liquid ghost! :) $\endgroup$ – Bithur Feb 14 '15 at 14:11
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Emitting smoke from rigged character is a matter of having the smoke modifier after any other (having the smoke last in the stack means it will use the final mesh after all the modifiers):

enter image description here

When using mocap for character motion or by having constraints on the bones, the subframes setting for the Flow object won't work and you will get this:

enter image description here

To fix it bake the animation action for your bones with Pose > Animation > Bake Action. Use visual transform and delete constraints.

enter image description here

With this solved I will focus on How to make smoke simulations really look inky.

  1. Every setting will depend on your Domain resolution and the size of your scene. That's why every showcase picture will have a downloadable .blend. Also the important settings are in bold.

  2. Enable Initial velocity for every Flow object. We want the ink to carry the motion of each object.

    • Lower the Surface emit distance and set Volume to 1.
    • Set Temp. Diff to -0.1 for every flow object so the smoke falls very slowly like ink in water.
    • You may also want to increase Sampling Subframes if your object moves fast.
    • For Ink Drop animations increase the Source above 1 and animate the Density from 1 to 0.

      enter image description here

  3. Domain setting: 256 Divisions

    • Time Scale around 0.3 (you may want to animate this for ink drops). Ink does not move as fast as smoke, this is important setting to make ink and not smoke.
    • Use Low Vorticity. This will be controlled with Turbulence field for the ink motion.
    • The ink can be nicely "faded" in post production, leave Dissolve unchecked or use some high number for Dissolve (like 150). Ink does not dissolve it will spread to thin with Turbulence field(s).

      enter image description here

  4. Add Turbulence field to the scene. This will create the important "dissolve" motion for the ink:

    • Its important to not overpower the settings! Too small scale or too intensive and the ink will look more like smoke or like there is too motion in the water and like the ink does not dissolve naturally. These settings depends on your simulation dimensions. Its also good to animate the Strength if domain Time scale is animated.

      enter image description here

  5. For Domain material use just Absorbtion volumetric shader with High Multiply Value:

    enter image description here

This results in ink like this (icosphere falling through domain):

enter image description here

Download .blend

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    $\begingroup$ can you add some images and examples of some of the steps? $\endgroup$ – cegaton Feb 8 '15 at 20:39
  • $\begingroup$ Also the ink morphs from one object to another following the same apparent turbulence, any ideas? $\endgroup$ – cegaton Feb 8 '15 at 20:40
  • $\begingroup$ @cegaton yep images are on todo, soon as I have them Ill add them. About that morphing I don't believe there is any. Its always faded or in camera cuts. I think the morphing text is in postproduction. I think of something though, maybe some shapekey morphing.. $\endgroup$ – Jaroslav Jerryno Novotny Feb 8 '15 at 21:45
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    $\begingroup$ @cegaton keyed particles go from one shape to another, then choose particle system for the smoke emitter. $\endgroup$ – sambler Feb 9 '15 at 9:11
  • $\begingroup$ @sambler powerful but tricky. really intersting anyway $\endgroup$ – Bithur Feb 9 '15 at 18:06
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here is my reference animation: enter image description here

Did a few tests and came back to particles. enter image description here
Just changed velocity from object to 0.4 in particles settings: enter image description here

Simplified and optimized things. Here is the domain setting. Quite simple, not that hires with only 100 divisions and no smoke hires.

domain setup

The domain material is simple as well. Basic black volume absorbtion but smoke density modified with a color ramp. enter image description here

The bird has 1 particle set. As it's a simple model with mirror, armature and subsurf, checked the "use modifier stack" option. Velocity from object looks better at 0.4 (see above render). Important settings are highlighted.

particles

The children have something special. Their number is animated from 0 to 5 and 0 again in 3 frames (very short) when i wanted the smoke to be more dense (when wings change direction).

The bird smoke settings:

bird smoke emitter

Compositing (vignette not included)

compositing

There's some really cool things with this setup. The "ink effect" (compositing) can be nice with a few render samples (used only 15). There's no light, no shadow (uncheck the option), only black smoke (added white background in compositing) renders in 5-10s for 25% HD size. The smoke sim is light weight too, 182Mo for 100 baked frames, and bakes fast.

About initial velocity : only working with emitter's surface and particles, not volume. Particles are better using no normal velocity but low object's velocity. Using children (simple, interpolated is for hair only) you need to check "rotation" and change the initial rotation to "normal" to get children poping at the surface of your faces.

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  • $\begingroup$ this looks great! Could you possibly share some of your set up? I'm curious about the particle side of things. I've not got a lot of experience with particles, and getting the particles to move dependent on the animation of the model is totally outfoxing me. $\endgroup$ – Jacob W.E Feb 10 '15 at 19:42
  • $\begingroup$ as it's a WIP, it'll be completed through the process, i had to give an answer to put a screenshot. $\endgroup$ – Bithur Feb 10 '15 at 19:52
  • $\begingroup$ @Bithur This is fantastic! Is the body emitting smoke or only the wings? $\endgroup$ – Jacob W.E Feb 10 '15 at 21:10
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    $\begingroup$ Both, 2 different system for better control $\endgroup$ – Bithur Feb 10 '15 at 21:20

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