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creating chips WITH FLEX - fem sim vs grains vs rbd vs something else?


anthonymcgrath

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hey chaps i'm trying to create a sim of some chips.   I want a big heap of them to fall on top of a burger sim i've done!

I've tried a few routes and just wondering what is the best way to go about this.

I've attached a scene - its a basic setup of some chips model.  I've made them packed and they fall.

however they are rock solid and just clearly dont have an air of bendyness to them.

what is the best way to go about this?


I tried FEM ....making one chip... solid embed... multiple copies then run that.  It seems to work in a fashion but soon as i turn up the amount of chips it becomes quite sluggish and also if some interpenetrate then you get wildly exploding meshes.
em.JPG.f4083da1c26347e6027f6499b715076e.JPG


I tried a wire solver but found the wires just seemed to do their own thing and not hold a shape or length.

I have got the rbd packed working but of course its just simple shapes and they dont bend.

I wondered if it might be possible to create a chip that comprises of maybe 5 simple boxes connected together with constraints?


attached a scene file below - theres a fem setup in there and rbd packed..
chips_sim_v003_rbd_for_odforce.hip

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On 28/06/2018 at 8:05 PM, ThomasPara said:

I think the rbd is the way to go on this one. Heres a simple setup to get you starting.

chips.hiplc

chips.gif

 

hey thanks for your help - this would be literally PERFECT for what i need wow thankyou :D


except i'm getting a different result here (houdini 16)... its like my chips just seem to break apart and dont hold together like they do in your gif.

I actually did a full rebuild of your scene and i've clicked all the stuff i need to but still getting this prob - any chance you can take a look at my scene and see where i went wrong please?  :/  (I dont have 16.5 as yet if thats the issue )

chips.thumb.JPG.98244edcd0e8b6ee3f31828b3e27b801.JPG


chips_sim_v006.hip

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Some minor things you forgot, the most important one was to set the right input on your Constraint Network. Since that was incorrect it couldnt find the Constraints. I also set your Goal Twist Axis and Constrained Twist Axis to X(1,0,0). But usualy this is Z on a curve where orientations is set. If you want to noise your curves before you drop them you need to set some orientations that follow the curve. I think Entagama has something on Parallell Transport or i could share my setup on fixing orientations on curves. 

chips_sim_v006_fix.hiplc

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20 hours ago, ThomasPara said:

Some minor things you forgot, the most important one was to set the right input on your Constraint Network. Since that was incorrect it couldnt find the Constraints. I also set your Goal Twist Axis and Constrained Twist Axis to X(1,0,0). But usualy this is Z on a curve where orientations is set. If you want to noise your curves before you drop them you need to set some orientations that follow the curve. I think Entagama has something on Parallell Transport or i could share my setup on fixing orientations on curves. 

chips_sim_v006_fix.hiplc

hmm i'm still having issues here - is this a H16 vs H16.5 thing because i open that fix scene and it just does the same thing sadly :(

the other thing is that i checked my dopnet and the constraint network and it is definitely plugged in as per your fix scene.  I just had to set scale to zero on the primitive node but beyond that i honestly cant see any difference in that constraint network unless i'm doing something wrong? 

I'm so close to this and yet so far lol

Capture.thumb.JPG.e1a44ad6e28fb7ff59fb114447e43bf9.JPG

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omg it was actually a really simple fix - i just pointed the constraint network path to my primitive and they showed up with nice little cone guides too which i've never seen before :D

fixed_yay.thumb.JPG.884ec14a95205fd853571292bce40b10.JPG


working nicely as you can see below!!!
 

woot.thumb.JPG.7f79dca7040d4b9d320b8c7b53ef232c.JPG

thankyou so much for your help and advice - i'm still not 100% sure how you set this up but i'm starting to understand that ability to create your own constraint network with wires and lines - which i guess is what the glue network does overall but this gives much nicer control!

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1 hour ago, ThomasPara said:

Cool, i dont think thoose chips are so healty for that burger!

And i forgot that they put that option in houdini 16, sorry about that.

 

ConstraintTab.png.3ea518d8fff67da8031bc3a7b4ab4b57.png

 

yeah proper chuffed with this technique its going to come in very useful for a few things i want to do!

yeah that geo source "second context geometry" isn't in v16 ...I added my path into the SOP path beneath it.  The new option must be a 16.5 thing.

gotta splat a load of ketchup and mustard over this burger and chips yet too hehehe.  then a small sprig of leafy green garnish :lol:
thanks again!

 

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