The current Setup:

I m working with RBD Simulation together with 4 Pyro Simulations(I might get up to 5 Pyro-Simulations for the Fire burning the Car after the Explosion)
This The RBD Simulations Node Tree:




The Situation:

The Particles inside the Explosion are not influenced by the visiable Fire of the Explosion but by the Blast Wave or Shock Wave that is invisable.
That means in that case the Explosion starts first just taking a small influence to breaking down the Car in Particles.
To make it physically right at the first Frames the Car just has to get some cracks and the Praticles move slowly in the first Frames.
The Reason is Light is faster than Sound. So the Blast Wave is actually breaking down the Praticles. Out of that is it clear that a Explosion has actually two Parts the Explosion and the Blast Wave starting to breaking down the Particles. So the Particles starting to move faster at that Moment when the Schockwave follows.


The Ideas:

1st Is it possible to animate the Density of my Collision Object? (probaly a bad Idea cause i think it has the same result when i render the first frame with a higher Density and than i render it in a new Houdini File... this might end just in dissorder, because the Collisions would look totally different)

2nd Is there Way to get my Collison Object at certain Time Frame in another RBD Solver? So that the Collision Object can react like in real Explosion: First the slowly developing Cracks from the Explosion and second the faster moving Particles influened by the Blast Wave


Conclusion:

Does it work somehow to get this Two Step RBD Result with Vex or just the current RBD Simulation placed in another RBD Solver?
When you have another Idea to get this Result please let me know.


I would also be glad for any Opinions on this Topic or any other Help to improve this RBD Simulation and this Project.

Thank you for reading
Enjoy your Day

I'm not sure I understand the problem... you talk about particles but it seems this is a straight up RBD sim?

I think you should get a pyro explosion you like, with a matching RBD sim of the car. You can then time-shift them appropriately. At some point you will want the RBD to influence the sim, but I'd start by blocking it out this way before bringing the RBD sim back into the pyro as a collider.

Then do a particle sim for debris and such with the pyro sim's velocity field as a force to advect your particles. You can then also time-shift this after simming to achieve the desired results.

mrCatfish
I'm not sure I understand the problem... you talk about particles but it seems this is a straight up RBD sim?

I think you should get a pyro explosion you like, with a matching RBD sim of the car. You can then time-shift them appropriately. At some point you will want the RBD to influence the sim, but I'd start by blocking it out this way before bringing the RBD sim back into the pyro as a collider.

Then do a particle sim for debris and such with the pyro sim's velocity field as a force to advect your particles. You can then also time-shift this after simming to achieve the desired results.

Thank you so much! This are great Tips to get an Explosion hyper-realistic. They really improved my Project.

Best Regards
Maximilian Paul