I spent the last few days working on a set of node groups for particles in geometry nodes, that I now like to share for free. You can see a few demos here:
Making particle simulations in geometry nodes always takes a few steps to do. Even if it is just for a few points that fly around. It involves particle lifetime tracking, velocity, and spawning new particles at a certain rate. So I created (hopefully) easy-to-use and understand node groups.
The Simulate Particles node group moves particles by their velocity but also removes particles whose lifetime exceeds their maximum lifetime. Spawn Particles By Rate creates new points with given parameters at a certain rate. Iâve added descriptions to most of the node sockets so you can get more insight if you like.
You can get the blend file from Gumroad (Needs Blender 4.0):
I share it for free and if you like to support me, you can buy me a coffee on ko-fi
The blend file contains these groups as assets, so you can save them to your asset library. It also contains a few examples. Many of them were also shown in the video above. I encourage you to look at my example node-setups to see how all these groups can be used together.
If you have any suggestions or feedback, let me know.
Ahh, sounds great!
Yesterday i tried to do particle collisions for a snowing animation and in blender they just bounce and yiggle a lot with standard particlesâŚ
I will try to recreate it with your solution, then we finally have a working collision system =D
Iâd like to share it in another thread, but these node groups often use a lot of node groups themselves. So it will be hard to make screenshots where people can see whatâs going on.
Should I then just add a few gifs like above from the particle systems and a link to this thread here? Also, I canât share the blend file directly since it is bigger than 5mb. ^^
Ah yes, I suppose that makes most sense then. I donât think that âreadable screenshotâ-rule can always be quite applied for practical reasons.
Itâs mainly meant in the sense of asking for something to reproduce or, if thatâs not practical, sourcefiles are fine too.
Up to this point, both particle systems have spawned around 1 million points while simulating them in parallel.
So in this example, geometry nodes seem to be faster. There might be other cases where the default particle system performs better. Geometry nodes on the other hand seem to cache these points better. So when I run the simulation again at the frames where it uses a cache I have 60 fps. But it uses a lot of VRAM. (It is also a lot of points on the screen )
You can also bake both geometry nodes and default particle systems to gain more performance if needed.
That said, this example is very basic and if you use collisions and more complex transformations on these points, performance will get worse of course.
Using nodes is just far more modular and flexible IMO thatâs why I made these groups in the first place. ^^
I hope simulation nodes will get sub-steps soon, as itâs clearly missing here (however, upping the subdivisions of the collision ico sphere already improves stability - while exponentially increasing the simulation time).
Edit: Ah, well, at 2 subdivs, itâs already damn stable.
Self collision is something Iâd like to add in the future presumably a bit more integrated and using less data to evaluate.
Using the points as icospheres can potentially slow down the computation since every vertex of every icospheres is evaluated. My plan is to check for collisions by distance between points and their radii.
Thanks for sharing though, it is a clever way getting it to work for now
Oh yeah, this was just a quick âhackâ, and Iâm not well-versed enough in GN to add it to your collision group directly. Iâve noticed that your current setup just uses point sizes to calculate collisions, which is probably way faster and more robust, so Iâm looking forward to get a proper integration by you!
Probably
You could divide the delta time by x substeps and run the particle nodes inside a repeat zone.
You might need to apply gravity and velocity (move particles) separately (there are separate nodes for it). The simulate particle nodes would otherwise spawn several particles per frame since it depends on the scene time. â put everything in a repeat zone except âsimulate particlesâ and turn off gravity and velocity there. Use âApply velocityâ and âadd gravityâ node groups at the beginning of the repeat zone. Use divided delta time for all the nodes in the repeat zone.
