LK Fill ParticleVolumes question to Leonard

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Bullit
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LK Fill ParticleVolumes question to Leonard

Post by Bullit » 21 Mar 2014, 00:59

Is your node LK Fill ParticleVolumes that you shared here https://groups.google.com/forum/#!topic ... z0WHeZ90pM

Possible to be changed for an uniform distribution? i.e all particles are at same distance from each other

To be able to do a moveable voxel like shown here: http://www.fxguide.com/featured/bifrost ... epth-look/

Leo
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Re: LK Fill ParticleVolumes question to Leonard

Post by Leo » 27 Mar 2014, 23:10

Hey Bullit,

sorry for seeing this almost a week after your post.

Unfortunately there is no super easy way that would be even within 2 orders of magnitude in terms of speed to do that, as far as I know.
The only thing I can think of is to build something which arranges the positions of the particles in a grid like way. The 3D Particle Grid compound that comes with Softimage would be a good starting point for that.
But for that to fill the volume of the particle blob you'd have to do some very clever array manipulation to skip certain positions in the 3d point grid, so that you'd get a spheroid.

If your demands are just a grid around each particle in a cube shape it will be easier, but still somewhat involved.

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csaez
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Re: LK Fill ParticleVolumes question to Leonard

Post by csaez » 28 Mar 2014, 20:56

What about using a highly subdivided cube (pcloud primitive) as a domain and removing the particles outside the geometry/container (point in volume node)?

Bullit
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Re: LK Fill ParticleVolumes question to Leonard

Post by Bullit » 29 Mar 2014, 08:35

Thanks Leo, csaez. My first try for this issue was to experiment with voxels compounds that are available using them in polygonizer mesh from particles. This idea was defeated because every frame the voxel compounds have to make new calculation and animation doesn't seem to be continuous. I'll have to try subframe.
I'll also try the csaez idea.

Bullit
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Re: LK Fill ParticleVolumes question to Leonard

Post by Bullit » 29 Mar 2014, 12:06

Cesar idea works using the polygonizer.

But the 3D Grid need to encompass the whole area of simulation. Not much trouble if the simulation is not big even if the area is.
Didn't tried to animate the point cloud position, since it think that is asking for trouble.

So an empty point cloud w/ 3D grid and Point in volume. Polygonizer mesh is the object that Point in Volume uses.
Of course also particle shape and particle size.

Bullit
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Re: LK Fill ParticleVolumes question to Leonard

Post by Bullit » 30 Mar 2014, 01:32

Now i have another issue, with instances this of course slows a lot , so is there a way to delete points inside?
So i am trying to copy the polygonizer and scale it down to have another Point on Volume to delete points inside, but my scaling of the polygonizer mesh fails because the center doesn't move with growing mesh.

Leo
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Re: LK Fill ParticleVolumes question to Leonard

Post by Leo » 30 Mar 2014, 15:25

Hey Bullit,

I have attached a compound which manages cloud instances as native particles of a cloud. It does take a moment to run, but it will be much faster to navigate or render.

I hope this helps.

Leonard
Attachments
LK_InCloudPointCloudInstances.jpg
LK InCloudPointCloudInstances.xsicompound
(38.66 KiB) Downloaded 104 times

Bullit
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Re: LK Fill ParticleVolumes question to Leonard

Post by Bullit » 31 Mar 2014, 01:10

Hi Leo, thanks for your help.

If i am understanding your compound right, it makes instances of a point cloud inside another point cloud.
I am not sure how this can help but probably didn't perceived your intention well. If i use a box of particles to replace the existing particles it center is the particles, so i don't see how can i not have an overlap.


I explain my steps and the existing solution so far.

1-I make a common particle emission, could be replicating water - like in fxguide example - or any other particle effect.

2-I cache it and apply LK fill particles to have much more particles with less expense.

3-I polygonize the modified cache

4-using Cesar idea, i make a 3D grid like in the image below that has the size of the whole simulation. With point in volume using the polygonize mesh to delete the not necessary points.
PC.jpg
5- when i have a very large polygonize mesh it makes sense to delete the inside points of 3D grid, that is what i am after now.

Option a)I tested making a thickness of the polygonize mesh and it works, it just more computational expensive.
Option b)I tested using a copy of polygonize mesh scaled down to subtract the inside points and scale does not work since the polygonize mesh has a fixed origin and obviously when there is splashes it needs to scale by point position/normal and not by origin. This is what i want to do now.


An overall improvement to all this was to not have the 3,4, and 5 and be able in 2 step to build an uniform point cloud based on volume of the existing one without the step of deleting the extra points. The excess internal points would still occur.

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Re: LK Fill ParticleVolumes question to Leonard

Post by csaez » 31 Mar 2014, 02:30

I would take the distance to the closest location on the polygonized mesh to determine/delete the inner particles ( if distance > shell-width: deletePoint() ).
It might not be perfect, but should work in most scenarios :)

Cheers!

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Re: LK Fill ParticleVolumes question to Leonard

Post by Bullit » 31 Mar 2014, 10:35

Done :)

Had missed the "not" node.

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