[Sidefx-houdini-list] particle fluid kill plane

Mark Elendt mark at sidefx.com
Fri Aug 12 13:14:26 EDT 2016


If you have the plane normal, (A, B, C), you can define an equation
for the plane:
    A*x + B*y + C*z + D
where D moves the plane up and down along the normal (from the
origin).

If you take a point (x,y,z) and plug it into the equation, positive
values mean the point is above the plane, negative values below.

So, in VEX:

    cvex
    partitionplane(vector N; float D)
    {
	float dist = dot(@P, normalize(N)) + D;

	if (dist > 0)
	    addgroup("dist", @ptnum);
	else if (dist == 0)
	    addgroup("onplane", @ptnum);
	else
	    addgroup("below", @ptnum);
    }

    
On Friday Aug 12 at 10:03, Gary Jaeger wrote:
> no that would work. A kill plane is just that. A plane that kills the particles. It can be at any arbitrary angle but generally I use them to kill particles in the Y.
> 
> I’ll see if I can figure that out :)
> 
> Gary Jaeger / 650.728.7957 direct / 415.518.1419 mobile
> http://corestudio.com <http://corestudio.com/>
> > On Aug 12, 2016, at 9:53 AM, François Duchesneau <sidefx at trinix.ca> wrote:
> > 
> > I've never used Bifrost. What is the kill plane?
> > 
> > If you're referring to a way of kill particles below a certain value in Y for example you could use an expression in the Kill Pop but I suspect what you're after is more sophisticated.
> > 
> > Francois
> > 
> > On 08/12/2016 12:35 PM, Gary Jaeger wrote:
> >> Noob question. Is there an equivalent to the bifrost kill plane for particle fluids?
> >> 
> >> Gary Jaeger / 650.728.7957 direct / 415.518.1419 mobile
> >> http://corestudio.com <http://corestudio.com/>
> >> _______________________________________________
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-- 
Mark Elendt



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