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  09 September 2012
Question Sandman

Hello everyone!

I'm looking to create an animated sandman with pflow and have him appear to be in a slow, perpetual state of collapse - the most obvious precedent of course being from Spiderman 3, although I also found a reconstruction of part of the shot that directly uses particle flow, too:

Spiderman 3 - Sandman
The Sandman HD (Done with pflow)

At present I've got a configuration with an animated mesh, with a Position Object and Lock/Bond node attached to get the volume of particles to update with the characters movements. I'm using keyed S/UDeflectors to erode parts of his form as required (such as an arm or a leg) which works well.

The issue I am running in to however, is getting secondary emission particles that run down his form and give the impression that he is in a perpetual state of collapse. Initial tests looked quite promising, but as soon as I began to up the particle amount it all tended to either fly directly downward, or behind him in a massive cape-like shape - his form either ended up being obscured, or the emitted particles wouldn't stick to the front of the character as he walked due to his velocity.

In order to get around this, I found a technique in a video here that utilized the Speed by Surface node (with its parallel to surface option selected.) In combination with an age test, the particles are born, flow down the surface then drip off after a period of time. The setup is here:

This works perfectly for a static mesh, but I can't quite seem to combine it with a lock/bond node in order to get it to follow my mesh as he walks. I'm relatively new to pflow, so am at a bit of a loss as to where to go from here. From the aforementioned link of the Sandman reconstruction is a breakdown of what he did here although due to it being so low resolution I can't quite make sense of what is going on. I've emailed him, but he hasn't responded yet so in the meantime I was just wondering what you all thought of it. I've also included image links below of his setup:

So yes, in summary:

I'm looking to create surface emission upon an animated mesh, and have the particles follow the mesh for a period of time before falling off.

Any help would be greatly appreciated, looking forward to hearing your thoughts/ideas! Also, if you happen to have any ideas for a completely different rig to get this kind of effect, I'd be really interested in that as well


  09 September 2012
I've never tried to do this stuff, but here is my quick morning (sleepy) opinion.
Are you trying to do all the stuff in just one Pflow? And why?
Why don't you just copy your Pflow, and brake apart that clone with randomized age test, and gravity (and perhaps some deflector on the ground)?

Sorry if I misunderstood you, but this is what I thought first.

Looking forward to other answers, and maybe I'll try to make the same effect.

Now it's the time to be extreme!
  09 September 2012
Hey d4rk3lf! Thanks for your quick reply

I assumed that I would have multiple pflow sims that would be combined at the end - naturally it would seem logical to have control over separate areas (Which could be controlled and restricted by emission based on various UVs assigned to materials, with isolated body parts.)

I suppose more than anything I'm interested in the way in which the particles behave upon an animated mesh - so that they are continually emitting from the surface, and falling in the rough form of the man. That happy balance between collapsing, and still having a definable form!

Would be really keen to see any tests that you come up with, it's an effect I've been interested in attempting to pull off for a while now
  09 September 2012
Also, a really rough render illustrating where I am so far, with no secondary emission - as the Youtube video says, I just quickly and roughly animated a deflector to run up the leg - the final animated character and deflector will be moving far slower, which should also help the look and avoid the awkward erosion of his form. (I am currently just using stock mocap data.)

I am also currently waiting upon a rigged character with properly deforming geometry, so ignore the initial "spikes" that appear! I am also aware that there is far too much wind, as I was playing with turbulence and forgot to turn the speed down -.-

Sandman WIP
  09 September 2012
I have a tutorial on this in store but i don't know if it's exactly what you are after:
  09 September 2012
Hello Anselm!

I was wondering if you might see this - I bought your tutorial a number of weeks ago which was a brilliant starting point, I attempted to modify the setup that you suggested but couldn't seem to quite get what I was after so went back to the drawing board to a certain degree -.-

Regarding the setup that you suggested - I found myself looking to further combine the two fundamental components of it; that is, the erosion of the sand from outside to inside, and also the use of XYZ Shaders in order to get "chunks" flying off. Within the setup I couldn't manage to dial down the simulation to be a lot more subtle (after trying to adjust the time multiplier, greyscale threshold and noise size) and quickly found myself with a character that had loads of "gaps" within a few frames of the simulation starting - chunks of sand such as the hand that were seemingly floating entirely in midair, disconnected from the rest of the body entirely. The effect that you achieve through the tutorial is pretty amazing - I suppose I was looking for something exactly like it but a lot more subtle, but thought it may be a bit cheeky to ask a million questions
  09 September 2012
sorry for the late reply.

have you tried making the gray scale map you use for the breaking of more subtle? like less harsh white tones? that should result in less deep gaps, etc. also the speed the character is moving in plays a role. If you want to lock the 3d texture so the character doesn't travel through it u have to throw a UnwrapUVW modifier on it. Also hand painting a map that grows is always worth a shot. that way you determine exactly what happens when and unwrap uvw your character and grow some masks over the uvw layout in after effects or what ever you use.

kind regards,
  09 September 2012
Finally I got some spare time to do a test.
Here's my attempt with no (pflow) plugins:

It's far from good, and definitely there should be more particles (and smaller), better render, and inter-particle collision.

But anyway, if somebody is interested it can look at the max (2011) file.
Attached Files
File Type: zip (185.1 KB, 13 views)
Now it's the time to be extreme!
  09 September 2012
i would lock the "eating" map with a unwrap UVW on top of the geo and make the gray scale map more severe so it "eats" more into the volume.
  09 September 2012
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