[SOLVED]Point max distance (Plasma look)

[cudarsjanis]

Hi. I have a particle sim where I have dense and sparse particle areas.

I would like to set pscale for all sparse particles close to 0.

I made this wrangle following Entagma tutorial with forloop, but when I apply this wrangle to the sim with millions of particles, it`s way too heavey.

Any other approach how I could achieve same result?

Attached there is hip. And using Cd just for visualization purposes.

 

Cheers

Janis

points.hip

Edited July 25, 2019 by cudarsjanis

[bunker]

you can try with pcnumfound(), have a look:
point_density_bunker_001.hipnc

[cudarsjanis]

9 hours ago, bunker said:

you can try with pcnumfound(), have a look:
point_density_bunker_001.hipnc

This works nicely. Just rendering now to see how it works for moving particle cache.

Thanks a lot!

I`m doing this post sim as I couldn`t get my particles do that in the sim. I used pop vop for vel update and was mixing v with noise to get particles more streaky together, like plasma. it works untill some point and then the further they get away, some of them just leave dense areas.

Basically I was trying to get whitewater foam like behavior, so sim is streaky.

any idea how I could use pcnumfound() in pop wrangle. where less dense particles would try to stick to areas where is more dense?

I`ll attach hip. How far I got for this plasma look.

Cheers

Janis

points2.hip

[bunker]

sure, you need 2 things:
- finding how many points are within a radius: with pcnumfound()
- finding the average position within that radius: with pcfilter()

// pointcloud handle (found points within a radius)
int handle = pcopen(0,"P",@P,chf("radius"),chi("maxpoints"));
// average position within a radius
vector p = pcfilter(handle,"P");
// point density (normalized)
float density = pcnumfound(handle)/float(chi("maxpoints"));
// display density
@Cd=density+{0,0,1};
// move points towards the average position
// particles with less density will move more
@P += (p-@P)*chf("regroup")*(1-density);

points3.hipnc

[cudarsjanis]

On 24/07/2019 at 10:50 PM, bunker said:

sure, you need 2 things:
- finding how many points are within a radius: with pcnumfound()
- finding the average position within that radius: with pcfilter()

// pointcloud handle (found points within a radius)
int handle = pcopen(0,"P",@P,chf("radius"),chi("maxpoints"));
// average position within a radius
vector p = pcfilter(handle,"P");
// point density (normalized)
float density = pcnumfound(handle)/float(chi("maxpoints"));
// display density
@Cd=density+{0,0,1};
// move points towards the average position
// particles with less density will move more
@P += (p-@P)*chf("regroup")*(1-density);

points3.hipnc

Dude, you`re a legend! Works perfectly. Just gonna adjust influence by age, as I need that only for the tips at the shot that I`m working on, and it`s done.

Thanks a lot.

Cheers

Janis

Edited June 7, 2021 by cudarsjanis