[Sidefx-houdini-list] Particle Flow

Michael Goldfarb goldfarb at corefa.com
Fri Mar 31 10:32:44 EST 2006


there is a video tutorial that might help....
http://www.cmivfx.com/tutorials.asp
Tutorial 40: Flowing Particles Along L-Systems Curves In Houdini

hope this helps


Dan Seddon wrote:
> Ben Schrijvers wrote:
> 
>> Basicly what you need to do to enable mixing your curve control with 
>> forces is modifying the acceleration rather than velocity.
>> Most of the other POP's work on acceleration as well and velocity is 
>> something to be very carefull with.
>> But you can't just use the attributeTransfer POP as this will 
>> overwrite the existing acceleration.
>> Also the acceleration that you need to apply is the difference between 
>> the curve velocity and the velocity of the particle.
>> So transfer the velocity to a custom attribute, subtract the particles 
>> velocity from it and add it to the existing acceleration.
>> You could do that with an expression in an acceleration POP.
> 
> Yep a controllable way of doing this might be to use Attribute Transfer 
> in combination with a Pop Vop. Use attribute transfer to find the 
> nearest point on the curve then make a Vop which produces an 
> acceleration or force which drives towards this point - you can also use 
> this positon to give yourself a nice falloff with distance. You could of 
> course use an expression - but I figure a Vop is easier.
> 
> Ta
> 
> Dan
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> 
> 

-- 
.......................................................................
Michael Goldfarb                            email: goldfarb at corefa.com
c.o.r.e. feature animation                       http://www.coredp.com
.......................................................................
"Unless you're an astronaut, secret agent, vampire hunter,
or all three, you're probably a sellout; screw you."
- Maddox 2003



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