Particles and Gravitation

[crahzz]

Hey Folks,

This is my first post here after a friend referred me to this website. I've been browsing through it and there is a lot of useful stuff on here but not quite what I am looking for at the moment. I'll explain a little bit about what I want to do (keep in mind Im a houdini novice)

I want to create a nebula with particles, and to be more specific the 3 elements most common in them. What I want to achieve is to have an emitter (or 3) to emit 3 types of particles with varying velocities (and amounts) that then exert force on each other equal to the mass of the particle. By doing this I want to form denser areas where particles are clustered. (part 2 of this project which I wont be working on is to detect density and spawn stars if the threshold is exceeded - stars in the appropriate spectral class based on the composition of cluster i.e Amount of helium vs heavy elements etc.)

If any of you have an idea of how to get the gravity to work - that particles directly attract each other (I have found some nodes that makes particles either attract or repel but as far as I could tell this would not be the right way to form clusters) please let me know =)

Thanks

[crahzz]

I was thinking that I could use smoke to visualize the nebula but I'm still not sure how to make particles interact with each other in the way I want to. Perhaps I could use the interact pop with negative attributes based on an expression that calls up the radius of the particle but I have no idea if that would be at all what I'm looking for. So if anyone has any suggestions on how to form clusters or denser groups of particles (smoke) let me know.

[rurik]

I was thinking that I could use smoke to visualize the nebula but I'm still not sure how to make particles interact with each other in the way I want to. Perhaps I could use the interact pop with negative attributes based on an expression that calls up the radius of the particle but I have no idea if that would be at all what I'm looking for. So if anyone has any suggestions on how to form clusters or denser groups of particles (smoke) let me know.

I have been thinking about a similar project, and I was directed to the Proximity POP. If I learn more about the process I will post here

Alex

[crahzz]

I have been thinking about a similar project, and I was directed to the Proximity POP. If I learn more about the process I will post here

Alex

I've been looking into that as well, it shows some potential but I'm not quite sure how to implement it correctly. Thanks for the heads up on that tho =)

So far I've been toying around with 2 ideas to generate a sort of gravitational field

1) have the heavy element particles spawn sphere's and use the attractor node to cluster other particles. (this might be to messy or complicated)

2) Use the smoke instead of the particles - create a positive multiplier for the temperature to heat it up and generate more smoke (at a certain point in the timeline) and after 'x' amount of time scale the multiplier back to for instance 0.8 to slowly kill it off.

both of these 'solutions' tend to work around the problem instead of giving a clear and straightforward solution. I'll dive more into the proximity pop and see what that does.

[crahzz]

No one able to help me out with this problem?

I was digging a bit more and am now looking for a solution within the proximity pop to orbit pop. I was wondering if I could detect nearby particles and make them stick together using those 2 combined with a property pop. Not quite sure if I'm in the right direction so help would be appreciated.