View Full Version : Particle fx - Pile of objects

03-24-2005, 04:47 AM

I'm trying to make a log break into wood chips which fall to the ground in a pile, over about 3 secs.

I have tried hard fx but there are too many wood chips (thousands) so the calculation is way too slow.

So I thought I would try dissolve out the log, then use particles and fx linker with the chips to drop them to the ground in a pile. But to do this I need the chips to fall on top of each other to build the pile up. But although I've turned on self interaction and everything else, I cant get the chips to actually stay on top of each other to build the pile, they just seem to slide off.

<In fact I'm having trouble getting interaction at all. I've tried doing tests where I've dropped 3 large particles onto a bouncy floor to see if they'll bounce off each other but it doesn't seem to work.>

I've been looking for tutorials on how I might do this but no luck, could anyone help/advise me on this?

Cheers, Alex

03-24-2005, 05:15 AM
Not really. It's that old problem of stacking marbles - self interaction is based upon a spherical collision model. I would try to "model" the pile based on an object emitter and then direct the chips towards the source using various forces and invisible collision objects. if you reverse the resulting sequence, you should get something usable.


03-24-2005, 06:24 AM
The will slide off each other unfortunately, as Mylenium says, PFx treats them as spheres, so imagine dropping a bag of marbles....

As to inmaking sure they interact.... things to check:

Your particles have size>0
Self Interaction is set to Bounce.
You hit Calculate.

Try pushing Force to 400% or more if it doesn't quite push enough.

03-24-2005, 12:19 PM
Theres a plugin called C4 which breaks an object up in modeler then reassembles it.

Then you can use hardfx and a collision object to make it break up into as many pieces as you want.

I only know of C4 as it came on the Inside Lightwave 8 DVD (that came with the book) so Im only assuming its around somewhere for free. Maybe on flay.com.

03-24-2005, 05:44 PM
Yeah, c4 is great for explosions and stuff, but it doesn't do particle to particle collisions unfortunately...

03-29-2005, 02:55 AM
Many thanks for that, I'm glad it wasn't me going mad, and that it's just how LW works. I think your idea Mylenium of modelling the pile is the best one and then either morphing or pushing the chips up and reversing it.

I'll have a go...!

Many thanks, Alex

03-29-2005, 11:00 AM
I cant get the chips to actually stay on top of each other to build the pile, they just seem to slide off.

Everyone above has better advice than this post of mine, but for what it's worth, "StopByStabilizer" is what you need turned on when making a pile of HardFX stuff. I wrote a thread about it here: