Better Surface Debris Option?

[Atom]

Hi All,

 

I am trying to emit some particles from an interior surface of a voronoi fracture.

 

The shelf tool create the debris source node and it works ok with edge debris.

 

EDGE:

 

 

But actually scattering along the surface seems to be poorly implemented.

SURFACE:

 

As you can see in the surface based version there is barely any surface coverage at all for the particles that are generated. I have specified the inside face group generated by the voronoi fracture node so there should be particles scattered all over the surface.

 

Is there any way to configure this system so particles are generated all over the surface and not just in the center of the surface?

 

NOTE: I have disabled the pop replicate so I could inspect the issue. But pop replicate alone is not the same as scattered coverage.

ap_test_debris_generator.hipnc

Edited March 16, 2016 by Atom

[michael]

inside debrissource1 you can turn ON Divide Non-Convex Polygons on the scatter2 SOP...

it helps a bit - spreads out the scattered points.

 

that said there is no reason you couldn't make major changes to the way this HDA does things....

[Atom]

Thanks for the reply Michael. I was playing around inside the HDA to try and solo various nodes and decipher the HDA operation. Your suggestion does help.  I guess the problem is with the particles generated. I assumed they would be generated from the scattered points but that does not seem to be the case.

 

In this image, the dark grey points are the scattered points and the white points are the particles generated. I would like a white trail of particles to come from each of those grey points. Event though the debris_sim particle generator does source in the OUT from the debrissource1 node, the particles generated don't seem to come from those points..?

Edited March 16, 2016 by Atom

[pockets]

I like to more explicitly control the points that get birthed by birthing from all points in the source. That way if I have 1000 points feeding the POP/DOP I get those 1000 points per time step, and then I use SOPs to both shape and control the number.

One of the ways I like to control the shape is by doing a fairly dense scatter and then add turbulence to Cd, letting me visualize the noise, and then delete the darker points based on a threshold. This can create some nice, organic, cloud-like volumes of particles that feed nicely into either advection by a velocity field or advection by curl noise. Generating the turbulence based on rest position means you get some coherence across frames and you can then do things like slowly shift the pattern over time or animate the threshold for culling so that the clumps of points generating particles "erode" in (or out).

I had to do some exploding blocks for a Minecraft-like spot recently and I did an additional density of noisy points near the edges of each surface and did two different passes of inputs for simulations based on a dot product against the velocity of the block. Point normals more or less in line with travel were used to source point stamped density for a pyro sim while points with normals that more or less trail the direction of travel birthed particles for trailing dust.

Rather than just being purely random and noise the bit of overhead in processing and visualizing the particle source inputs has been worth it to achieve results that I can influence in ways other than jittering seeds and scaling up and down density.

Edited March 21, 2016 by pockets

[Atom]

Thanks for the info.

 

I guess I am less concerned about the scattering of the grey points. I am more concerned about the fact that the grey points don't emit particles. The white streams just appear as they do. What part of the system do I adjust to make a white stream of particles emit from every grey point?