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derjcmp

(NOVICE) Attatch POP Grains to deforming geometry

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Good evening everyone!

I'm trying to attatch my pop grains to a deforming geometry. 

I've tried seeing everything related to pop particles on the forums but nothing worked.

Thanks for those who help !

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Hello. Do you want the POPs to "stick and stay" on the deforming geometry surface? I am unfortunately no guru, so my attached solution is not maybe ideal. But it is working for me. Further about the collisions, I recommend you also this ... https://vimeo.com/182074285  ... at the beginning, Jeff talks about the Deforming Object shelf tool and more about the volume collisions and static solvers and troubleshooting.

attach pops - v0.hiplc

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That wasnt the type of effect I was looking for, however it showed me a good technique I didnt know!

The type of effect Im after tho is like having a Derfoming geometry with the grains all over the surface on frame 1 and moving with with the geo until the end. I tried sticking them in a static position and then interpolating it with the deformed geo after the simulation, but that didnt make any sense in my head nor in houdini. I thought It had to be an easier way, perhaps through a multisolver and some vex, idk. 

Thank you.

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Hello João, I see. I think that this may also help you:
http://lab.ikoon.cz/post/148412813139/inspired-by-the-sop-examples

I made that file from the help example file (SpikyDeformingTorus.otl) and I use the Attribute Interpolate. However, it is not a DOP, but SOP solution:
https://www.sidefx.com/docs/houdini/nodes/sop/attribinterpolate

That example file is well documented and it may also help you :)

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I was looking for a dop solution :/ I've tried your method but didnt give me the results I was after.

I'm going for an effect like this: 

The fallof part I can easily do, however sticking the grains to the geo is really hard

 

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Did you suss this out J ?

It's something I want to do too.. fill an object with grains and have them deform with my alembic mesh.

 

Just thinking on my feet.. essentially they are all connected via a glue network of connected lines.. it may be easier to deform that as such and hopefully the grains will go for the ride till you choose to break them?

 

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I didn't manage to pull this off :(

I tried like 10 different approaches and all of them didn't work as I wanted. I could stick them as scattered points and add a copySOP to make them grain like then doing a RBD sim, but I couldn't get that particle to particle interaction without heavy compute time...

I asked it on /r/houdini and some pretty cleaver solutions came through, will give it a try when I have more time! 

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Doh, immediately after I posted realised how to make it be fully dynamic rather than switch, if you need that level of detail. Here I've ramped the targetstiffness from 0 at the feet to 1 near his waist, then turn it off completely after frame 41. 

grain_dancer_v02.hipnc

grain_dancer_v02.gif

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holy potatoes @mestela that is exactly what i was after thankyou!!!  the second trick is perfect!

big fan of your work btw - recently watched the sidefx seminar you did - learnt a ton thankyou!

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1 hour ago, mestela said:

Doh, immediately after I posted realised how to make it be fully dynamic rather than switch, if you need that level of detail. Here I've ramped the targetstiffness from 0 at the feet to 1 near his waist, then turn it off completely after frame 41. 

grain_dancer_v02.hipnc

grain_dancer_v02.gif

Went through the file, pretty cleaver! I guess I still have a long way to go inside houdini. Thanks matt!

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just rebuilt that scene myself now thanks @mestela works a treat :D

wasn't working till i realised in the second wrangle there was a ramp thingy at the bottom - was scratching my head for a bit hehe!

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10 minutes ago, derjcmp said:

Went through the file, pretty cleaver! I guess I still have a long way to go inside houdini. Thanks matt!

its insane - there must be 50 ways to do every trick in houdini its scary.  There was a bit of wrangle in there that just made me go 'huh'

i'm not adverse to it at all but i have no idea whats happening with each bit really and i cant help but think 'is there a sop solution to this for my noobness to get my head around' lol

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I went through and added some AA noise, did a fit range and mult it by the stifeness, Im getting exelent results!

Also did another wrangle so it would colapse if @targetstifness was < 0.3 . I guess I'll be playing with this all night!

Edited by derjcmp
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1 minute ago, anthonymcgrath said:

jeez i've no idea what you just said but it sounds cool lol!

Instead of having ramped the targetstiffness from 0 at the feet to 1 near his waist I did a noise. So some parts start to crumble as the others just follow the geometry :) 

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7 minutes ago, derjcmp said:

Instead of having ramped the targetstiffness from 0 at the feet to 1 near his waist I did a noise. So some parts start to crumble as the others just follow the geometry :) 

ooooooooooooooooo that sounds smutty!!  :D  cant wait to see that :D


here's my current progress... sorry about the crap gif quality - fairly new to it... so basically i have a ragdoll crowd group i setup... then exported that out as alembic... then pulled it into this setup @mestela did for us and twiddled the values so the stiffness goes once they're knocked outwards :)  there's prob smarter ways but its working for me :)
 

crowd_ragdolls_to_grains.gif

and look!  look!  I did a gif!  screen2gif rocks :D

Edited by anthonymcgrath
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