Kill isolated particles

[Navneet Arora]

Hey guys,

Any way of killing isolated particles? Like we do in realflow . I am trying to do a point cloud lookup but not able to figure out how it would work. Any help would be appreciated

[Navneet Arora]

I found the solution, did point cloud lookup and on the basis of number of points found i transferred them to another group and deleted them.

[origin]

without grouping

int handle = pcopen(0, "P", @P, radius, 5);
if (pcnumfound(handle) == 1)
  removepoint(0, @ptnum);

[Navneet Arora]

Thanks for the reply. I did the same thing inside vopsop, thanks anyways

[tious13]

Hi could you upload a basic hipfile on how to apply this script or vopsop ? It would really help for I am fairly new to houdini .

Thanks 

[tjeeds]

You can use a POP Proximity and POP Kill node to handle this. Less headache than using a wrangle and accomplishes the same thing.  

[johnLIC]

I could really use a hand implementing this in a VOP or pointWrangle node.  I tried putting the VEX (?) code above in a pointWrangle, but got an error saying that pcopen was unrecognized.  Anyone?

[Jero3d]

The reason why it's not working is because you need to declare a variable called radius (or have a number instead of the word "radius"). You just need to add one line before that:

float radius = 0.1;
int handle = pcopen(0, "P", @P, radius, 5);
if (pcnumfound(handle) == 1)
  removepoint(0, @ptnum);

 

You could also set it to float radius = ch("radius"); to create a parameter and be able to control it through a slider. I attached an example using Origin's code in case you want to see how to apply it.

kill_isolated_particles.hipnc

[johnLIC]

HI - thanks.  I figured that out about the radius.  Now I'm just trying to make it work in a simple scene.  Your file works perfectly.  I was trying to set the same thing up in a flip autodop network, but no luck.  I tried changing the last line inside the if statement to "dead = 1":

 

float radius = .004;
int handle = pcopen(0, "P", @P, radius, 5);
if (pcnumfound(handle) <= 4)
  dead = 1;

 

 

...but no luck.  I tried it after the source volume for the emitter, and in the particle velocity input of the flip solver.  Any ideas on doing it in a flip sim?

 

I tried turning on the droplet tab and killing droplets, but it isn't behaving as expected.  I've got some very lonely particles that refuse to die, but the droplet function did thin out a lot of areas that didn't need it, imho.

 

[johnLIC]

I got it working before the meshing, after the "import particle".  I'd like to get it working in the sim, but at least something good is happening.