Uniform paticles on a object surface

#1

Hi.

Any suggestion on how to uniformly place paticles on a object surface. When using Position Object the particle placement is a bit too random leaving a lot of gaps unless a lot of particles are used.
The new Krakatoa GeoVolume is great, but cant quite handle my 3000 sphere emiters :slight_smile:
I have created 6 diferent partitions with 6 million particles each, to cover the 3000 spheres, but still the 36 Million particles leave a lot of small gaps. Any ideas how to make ly life easier and not having to create another few partitions.

#2

I’d recommend using Birth Texture operator, with type = Face and Subdivide ON, with totally white texture for uniform effect. For better effect the original spheres are better be of GeoSphere type.

The placement of particles here - http://www.orbaz.com/gallery/?id=10 - is done with Birth Texture.

Thanks,
Oleg B.

#3

Sorry, I don’t really know PFlow, but maybe you could try a ‘dart throwing’ method to get pretty good distribution i.e. randomly sample the surface, if sample is not within a certain radius of a particle then add another, else sample again.
Might be pretty slow when your surface is nearly full though…

#4

Carlos, you could try increasing your voxel size and/or increase the voxel filter radius even just a little to help fill the gaps. (of course I am assuming you are rendering in voxel mode), I’d give it a shot before you go and re-PRT’em anyway.

BTW I think it looks pretty cool the way it is, has a nice bit of surface randomness look to it :slight_smile:

#5

Thanks Oleg, gonna give it a try.

@ Johnny: incressing the voxel size doesnt help as the balls will be spanning particles by travel distance, and then at some point the whole lot will turn into a a pile of dust :slight_smile:
Larger voxels will make dust particles too big.

Cheers

#6

We were discussing the addition of a GeoSurface modifier which would tessellate internally and produce any number of particles in an arbitrary surface. If you would start with a geosphere where the vertices are more or less uniformly placed and the face sizes are also uniform, it would cover the surface pretty nicely. In fact, you could just get a geosphere with a lot of segments and use its vertices. But since you want this inside the PFlow, follow Oleg’s advice.

#7

Birth Texture operator,does a fantastic job. My only problem now is to get it to work with all the 3000 Geosphere emiters. So far managed to include around 700, before Max crashes. I guess I’ll just have to create several different emiters and load into them as much emiters as possible.

#8

New issue: The particles are not following the emiter balls within the Flow, even though they do follow ok on the Birth Texture guizmo.

#9

I just did a test with a simpler scene and just realised that Birth Texture doesnt update every frame(am I right?), altho my idea from the help file was that it doesnt need a Position op.
It did work by using a LockBond after the BT.
Thats totally overkill for my 3000 sphere setup.

#10

Was now trying the Krakatoa GeoVolume aproach, applied the modifire to the spheres, saved the particles as PRT and then loaded them into my PFlow. All worked nicelly, but when I tried to create different seeds, the Random Seed doesnt seem to have work.
I’m using the lowest grid spacing (0.1cm) and Shell start 0 cm, thickeness 0.1

The initial Geosphere had 180 faces, I then put a Turbosmooth (2160 faces) under the Krakatoa GeoVolume
The amount of particles per sphere is around 44000.

#11

GeoVolume does not do any jittering yet, so the seed plays no role in the current Beta.
But you can load the PRTs back in a PRT Loader, add a high-frequency Noise (Scale 0.1, a bit of Strength along all 3 axes) as shown in our online tutorials about partitioning imported particles, and re-partition that. The Seed of the Noise can be incremented (be sure to check the respective option in the Partitioning rollout) and you will end up with a lot of versions of the same GeoVolume. Then load all Partitions again in a PRT and resave as a single PRT sequence and delete the old partitions to save disk space if you want. Then you can load the new combined cloud into PFlow.

#12

Cheers Bobo,
Yep, I guess will have to do it the hard way :slight_smile:

#13

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