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anthonymcgrath

sop solver and crumbling grains via volume vop and wrangle woes

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hey guys i'm properly having my chuddies rubbed here.  I've got a scene where i have a simple walk cycle character.  I'm trying to get him to crumble away but for the life of me i cant get the bloody thing working!!!

I've tried putting a colour on the character, then a group with a few red points.  then i'm using a small wrangle code from a yt tutorial to 'infect' outwards from those red points.
I've tried this in the sop context and in the sop solver within dops and its biting my ass big time now.  I cant understand what i'm not doing right.


in the same scene i'm also doing the same trick with a sop solver and a pointvop for noise/colour
this works ok but the character moves 'through' the 3d noise and those grains fall away - but i cant suss out how to lock that 3d noise down so it moves with the character as opposed to him sliding through it :/


can anyone help here?  I'm at my wits end with sop solvers - i've a feeling i'm close but its that final tweak just to get it to work thats eluding me :(

I've included a scene with the two examples/fails and my walk cycle alembic for you

cheers
ant

GrainWalk4_using_infect_wrangle.zip
 

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well i seem to have sussed it a bit.. just moved the wrange with the @infect=1;  back into the sop network just after the TO_DOPS null

in the sop solver within dops i now just have my wrangle with the searching code

and it works.

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nope am back to sq1 - so basically i tried to use a group node that moves down through the grain source (character) but that doesn't seem to pass through into dops.  I tried copy pasting that stuff into the sop solver in dops and the points just move back to frame1 because of the timeshift.
 

grp.JPG

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nope hang on - it IS working - but it needed a first red point in there in order to work so just shifting the group node down a touch at the start frame meant the sop solver in dops had something to start with.

its a little infuriating tho as my character now starts crumbling away from frame1 whereas it would be nice if he could walk for a couple of cycles then start to crumble away

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As you say, you were super close.

All I did was split out the stuff, and be lazy with how to control the growth timing. The solver growth is in its own sop solver, running on the static points rather than the deforming ones, just so it was easier to debug.

Basically the same technique you were using, to control the timing all I did was enable the bounding box controls for the group where you define your seed points, and keyframed it to wipe through the person so it starts above his head (thus meaning no seed points are defined), then wiping through to his feet.

The dopnet is just the grain sim, the only extra bit I had to do was to make sure it copied Cd from outside the sim, otherwise it never inherited the growing 'infection'.

GrainDancer4_using_infect_wrangle_fiddle.hipnc

grain_walk_collapse.gif

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@mestela ah Matt literally as you posted this i just realised i could use a vertical bounding box much like you did :)  however what i didn't know is you could specify a range of random points AND the bounding box together in the same group node!  I was trying to join two of them together and all sorts lol!

Then of course you have the sop solver in beneath it to grow the colour.  so in my other example in the scene i should be able to do something similar with the pointvop (for colour) - animating the fractal amount within a sop solver hopefully.

thats super impressive and works really well!  thankyou once again :D

 

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no probs. don't forget with this sort of thing you may not even need a solver to define the growth pattern; some noise run through bbox based ramps and whatnot will probably be fine, and save you having to use a pesky solver.

 

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I just read Anthony's message to me on Twitter about his problem but seems I was late to the party... :D

One thing I thought about with all these types of setups is how to get limbs to detach in DOPs when their connection to the body is lost - like in your file, Matt, the connected grains in the arm should all be falling the second the connection between the arm and sholder is dissolved.

Gotta admit, though, I haven't thought about it in regard to grains but rbd, like the fracturing deforming mesh setups posted here (and at CG Wiki). :)

 

Edited by Farmfield
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3 minutes ago, mestela said:

no probs. don't forget with this sort of thing you may not even need a solver to define the growth pattern; some noise run through bbox based ramps and whatnot will probably be fine, and save you having to use a pesky solver.

 

yep thats acutally what i was kind of hoping to be able to do but from what i'm learning most ppl nearly always pass some sort of colour info via a sop solver so my limited understanding was that was how it needed to work :/

if you have a method using the way you just described with bbox and ramps i'd love to see that!  no rush tho - this one works a peach :)  altho gotta say i wrote that wrangle as you did with a 'how the hell does he know this?!' - i'm trying to learn that stuff but its so complex... mind i've been an animator for 18 years+ not a coder really so even wrapping my noodle around the syntax can get complex for me...

if you need giant leviathans clobbering one another and going all charles atlas at the cam tho i'm yer man heh!
GM_20170128_195347.gif
 

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@mestela - yep got this setup working nice now

whats really nice about your setup is that the grains now seem to work nicer with the colour... in that if i adjust this bit..

if (f@Cd>0.5)

{

@targetstiffness = 0;

}

and i raise that 0.5 number the grains seem to hold on longer till the point is almost fully red then they become active - its really nice and gives a subtle impression of heating up before melting i guess!

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