françois puren


About Me

Advertising / Motion Graphics



Houdini Skills


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Recent Forum Posts

Particles spiral motion 2016年8月5日12:02


I'm facing a problem, and can't figure it out alone… (yes, that mostly always the reason someone post here i guess :p)

I'm trying to make some particles firstly go in a spiral motion around a curve (I've succeeded in this part with a line with edge_dir, then a wrangle with pcopen, and some cross products), but i want at some point (based on age) for the particles to end in tiny spirals… Like the effect in the frozen movie for exemple.

As my particles are firt moving in the XZ plane, i just made a first test by cross-producting the vel by an {0,1,0} vector, but evidently, as soon as my particles move in the Y direction, this method stop working!

So i think i just need some “up vector” from the particles, but that were i'm stuck!
The particles could be with any velocity direction and “spiraling” in any direction too…

So, does anyone knows how i could find this upvector, which should be pointing down when the particle is at the “top” of a spiral and need to get down, etc?

I hope i explained it well enough, sorry for my english!

Thanks a lot in advance!

Make an object constraining a controler in my DA rig 2016年6月22日16:42

I will as soon as i can, thanks Arctor.
I was thinking (don't know how hard it could be) that an option like the “keep position when parenting” could be nice, like “keep position when blending” :p
I'm not a technical guy at all, but i guess it's a trick with inverse xForm matrices, right?

Make an object constraining a controler in my DA rig 2016年6月22日11:08

That worked quite well, thanks Arctor!
Even if i'm not able to keep the current position of the hand as it worked in maya when creating a new constraint, it will do the trick for now.