Really useful explanation, thank you for posting this video! However, I would suggest to remove the overlaying text after a bit from the beginning of the video, as it overlaps with the command prompt and message log, and perhaps make the camera PIP smaller and placed somewhere where is less likely to have important information (maybe top left?) Other than that, great stuff!
@@glay011 introduction to niagara covers the basics of collisions. Then I look at obstacle avoidance in the advanced course and inter particle collisions in simulation stages
Note - Cpu - For Ai and Physics etc Gpu - For Drawing - Gpu information to cpu is costly , so cannot simulate Collisions on Gpu , has to be done in CPU - For Huge no of particles do GPU sims or will be heavy cost on cpu
@tharlevfx I am facing an issue with the Collision node which is my particles die the second they hit and object! I do not want them to die ! I need to keep them in an infinite lifetime. And when I deactivate the collision node, they stay alive.. so I am 100% sure it is the collision node that is killing them after contact ! And I am currently using GPU, distance field collision. Do you have any idea how I could keep them? Thanks!
Sorry, what does it means to use DirectRead? I have an exact situation that I'm trying to use GPU as the collision spawned particles. Since I can't use CPU event handler to pass GPU, what is the proper way to do the DirectRead method? Thanks
Hi ! How can we have self colliding particles ? I need to fill a container with particles but particle don't stack on top of heach other. Is it possible to have a kind of self repelling particles ?
its not simple i'm afraid - if you look at epics content examples they do something there to set up particles with particle collisions but i've never tried it myself
so i'm not an expert on programming but i think you still have to package up your compute shader to work with the existing hardware - so for example you couldnt use a compute shader to both calculate physics collisions and then also spawn something based on those collisions, in the same frame.
Is there a way to get some data on surface the particles collided with? I need to spawn particles flat against collided surface and I just can't find a way to do it. Even default collision modules just use location read/write nodes...
i think if you need surface data information then you need to use line traces in blueprint, rather than particle collisions - i might be wrong though. check out the niagara examples in the content examples project - there's some more advanced techniques there with things spawning and changing colour based on collisions.
@@tharlevfx I just finished doing exactly that. I'm tossing some particles on the ground, they fire the blueprint event, each of them has line trace based on their position/velocity vectors, then I spawn new system on the hit location with one particle in it. The performance of this setup is just absolutely horrible. I'm hoping that IF it's possible to get surface normal in Niagara, it'd work much better... maybe. I didn't find anything I could use in content examples. The color changing thing is pretty much updating color based on "HasColided" bool. I'll keep digging though.
Thanks for the video, however, when I do this, I get the burst FX spawning at the initial location AND on collisions. I can't seem to get the burst to only play on the collision even itself. Have you seen this?
ooo....never mind.... I had a spawn rate on the 'burst' too. Setting the spawn rate to 0 and setting Spawn Number in the Event Handler Properties fixed this :)
Hi How to spawn emitter on location of particle collision (death)? Basic event handler spawns only on burst particles on location, but not an emitter. Thanks
Example: Dummy fall by the gravity, has collided, generate death event and location. Fire emitter 10 second and particle lifetime 2 second receive death event and location. But spawn only particle 2 seconds and that's all. No emitter 10 second living
@@AntonyCatdog ah i understand - i'm not sure you can use a collision event to trigger a spawn rate particle from a position natively. you might be able to use a blueprint event to spawn a new emitter at the collision location but i've not tried that with niagara yet. its almost certainly possible using a custom module but i'm afraid i dont have experience with that either.
@@AntonyCatdog this sounds like a problem better solved by using a physics object for the dummy and then spawning an emitter via blueprint on the physics collision, rather than just using niagara. or via a custom module as i mentioned above.
if you're using CPU collision then theres an option to advance the aging rate, just set that to a very high number and it will work as a kill on collision.
@@tharlevfx Thanks for the quick response! I took the default third person structure and flipped one of its walls up into a ceiling. So, the particles should be treating the actor as a collision object. I cranked advanced aging up to 100,000,000 and I still have particles passing through my ceiling. It appears there are more falling outside than under the ceiling. It appears some particles are colliding whereas others are oddly passing through.
Paul717 are you using cpu or gpu particles because they collide differently? Have you tried the analytical planes rather than mesh collision? Sadly particle collisions aren’t perfect so you might just need a different solution.
@@tharlevfx I'm new to Niagara so a lot of this is stuff I'm not familiar with. I have requires persistent IDs enabled. Sim Target is set to CPUsim. Collision is set to CPUsim. CPU collision type is raytraced. Collision is enabled. I'm read the tool tip of CPU collision type and it appears raytraced is what I need cuz I need the rain drops to collide with a variety of objects such as buildings, terrain, water and the third person character. The analytical planes looks like it would be limited in that regards. I've been doing more research, and some of the things that might work is kill planes, onparticlecollide event, and particleshascollided. I just don't have enough experience to know how to implement these, yet.
@@Paul-hw7kc yeah unfortunately particle collisions probably just arent reliable enough for this use case. the easiest thing might be to expose a lifetime parameter to your system and then just manually place your fx so that the rain doesnt go through the building. dealing with Rain fx in games is quite a known complex thing i'm afraid.
If, like me, you came here to learn how to use Collision Events to spawn GPU particles this is NOT a tutorial for you. This tutorial only shows how to use CPU particles in collision context.
@@tharlevfx Absolutely agreed. Just the title of the video could be a bit better. What I saw in a video titled "GPU Particles and Collision Events" wasn't what I was expecting.
@@tharlevfx That being said, credit where credit's due. Very good video overall! I ended up giving a thumbs down, due to only finding out at the very end of the video that I didn't find the solution I was looking for. In hindsight though, I feel I overreacted, so would rectify it.
Very helpful video! Quick question: How can I use the collision event of a CPU particles emitter inside BP to make any sort of action on colliding and not just other emitter responses to the collision? I hope it was clear and thanks again
Idan Ben-moshe I’ve not tried it with niagara but you definitely used to be able to create blueprint events from cascade particles - I made a video about it
Sadly not, collisions between particles would be too expensive for real-time. You could try making a blueprint that spawns lots of little physics meshes but that might be expensive on the frame rate
@@tharlevfx Gotcha, thank you for the quick reply. How about emitting invisible physics meshes with collision enable sprite emitter in the same systems, do you think the two systems in front of each other will simulate collision like effects? Or would only the meshes collide while the sprites go through? Thx
@@tharlevfx I'm trying to make wo flamethrowers flames colliding, I have a great sprite emitting particle system that collides with the world, good fire spreading effects on collision with meshes or skeletal meah.. . But when fire meets fire I want them to collide in the middle. I hope my imagination came through
@@idanben-moshe1317 so I would maybe try having an invisible collision mesh the same size and shape and as the flames and then line or sphere trace forwards the same size and shape again - if the trace hits the collision then spawn a new effect for the flame collision, maybe shortening the lifetime of the two flamethrowers appropriately
Hi thank you for the great video. What would be the most effective way to kill particles as soon as they collide with meshes in your world? Like rain hitting a roof or ground. The moment they touch they get nuked. TY :-) Also is it possible to create "hold out" volumes, volumes in the middle of your world where you DONT want particles to spawn or enter or pass through.
In niagara there’s a kill module and a hascollided property - if you connect them then once they collide the particles will be killed instantly. You could also use this to definite a volume where particles are killed with a little bit of math
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So eloquently explained, thanks so much!
Swiftly becoming a computer engineer from your videos as well. Beyond worthy.
Really useful explanation, thank you for posting this video!
However, I would suggest to remove the overlaying text after a bit from the beginning of the video, as it overlaps with the command prompt and message log, and perhaps make the camera PIP smaller and placed somewhere where is less likely to have important information (maybe top left?)
Other than that, great stuff!
I periodically look at this video to revise some basics, thanks
I thought you were my lifeline for showing me how to use collision events with gpu emitter... but then 13 minutes later, i was dropped dead.
If you check out my intro to niagara course I show how to replicate all the events on gpu
@@tharlevfx Which course is about GPU particle collisions?I want to buy
@@glay011 introduction to niagara covers the basics of collisions. Then I look at obstacle avoidance in the advanced course and inter particle collisions in simulation stages
THANK YOU! You are a lifesaver for this video!
Thanks, that looping bit was something I got stuck on for triggering another emitter on collision. So unintuitive.
Superb job. Nicely organized. You saved my day!
Mandatory comment to support this video. Thank you very much!
Note -
Cpu - For Ai and Physics etc
Gpu - For Drawing
- Gpu information to cpu is costly , so cannot simulate Collisions on Gpu , has to be done in CPU
- For Huge no of particles do GPU sims or will be heavy cost on cpu
Thanks for the awesome content! This tutorial really Helped me!
Thx 4 the background knowledge! Awsome content!
@tharlevfx
I am facing an issue with the Collision node which is my particles die the second they hit and object! I do not want them to die ! I need to keep them in an infinite lifetime. And when I deactivate the collision node, they stay alive.. so I am 100% sure it is the collision node that is killing them after contact ! And I am currently using GPU, distance field collision.
Do you have any idea how I could keep them?
Thanks!
Sorry, what does it means to use DirectRead? I have an exact situation that I'm trying to use GPU as the collision spawned particles. Since I can't use CPU event handler to pass GPU, what is the proper way to do the DirectRead method? Thanks
nice video, thank you! i'll try it out in my project :)
sooo, why is his fps way down at 45fps while he only has a few particle effects in an empty level?
The video encoder takes up quite a lots of the gpu time
Hi ! How can we have self colliding particles ?
I need to fill a container with particles but particle don't stack on top of heach other. Is it possible to have a kind of self repelling particles ?
its not simple i'm afraid - if you look at epics content examples they do something there to set up particles with particle collisions but i've never tried it myself
Good video! Just a quick caveat, the GPU can definitely process information and send it back to the CPU. Check out compute shaders :)
so i'm not an expert on programming but i think you still have to package up your compute shader to work with the existing hardware - so for example you couldnt use a compute shader to both calculate physics collisions and then also spawn something based on those collisions, in the same frame.
A question ---- how do I create Collison query in ue5
hello, how to spawn decals at the place where niagara particles collide with the floor?
You shouldn’t really use particles to spawn decals - use a line trace or physics collision instead.
Is there a way to get some data on surface the particles collided with? I need to spawn particles flat against collided surface and I just can't find a way to do it. Even default collision modules just use location read/write nodes...
i think if you need surface data information then you need to use line traces in blueprint, rather than particle collisions - i might be wrong though. check out the niagara examples in the content examples project - there's some more advanced techniques there with things spawning and changing colour based on collisions.
@@tharlevfx I just finished doing exactly that. I'm tossing some particles on the ground, they fire the blueprint event, each of them has line trace based on their position/velocity vectors, then I spawn new system on the hit location with one particle in it. The performance of this setup is just absolutely horrible. I'm hoping that IF it's possible to get surface normal in Niagara, it'd work much better... maybe.
I didn't find anything I could use in content examples. The color changing thing is pretty much updating color based on "HasColided" bool. I'll keep digging though.
Thank you so much!!!!!!
is it possible to just spawn once insted of infinite? cause im trying it and its not working. Also great work man!!
If you change the emitter loop to Once and then use a spawn burst instead of spawn rate it should just happen once.
@@tharlevfx yep, It was that. Thanks a lot🙏
Thanks for the video, however, when I do this, I get the burst FX spawning at the initial location AND on collisions. I can't seem to get the burst to only play on the collision even itself. Have you seen this?
ooo....never mind.... I had a spawn rate on the 'burst' too. Setting the spawn rate to 0 and setting Spawn Number in the Event Handler Properties fixed this :)
However....how do you set a particle to 'kill on collision' like you would in Cascade?
Peter Clark you can set an age multiplier to be really high and kill them off with their lifetime
Thanks!
Hi
How to spawn emitter on location of particle collision (death)?
Basic event handler spawns only on burst particles on location, but not an emitter.
Thanks
Antony Catdog are you also generating the location data?
@@tharlevfx Yes, location is okay. But it's only burst. not a emmiter that lives< expample 10 second. It only lives of particle lifetime
Example: Dummy fall by the gravity, has collided, generate death event and location.
Fire emitter 10 second and particle lifetime 2 second receive death event and location. But spawn only particle 2 seconds and that's all. No emitter 10 second living
@@AntonyCatdog ah i understand - i'm not sure you can use a collision event to trigger a spawn rate particle from a position natively. you might be able to use a blueprint event to spawn a new emitter at the collision location but i've not tried that with niagara yet. its almost certainly possible using a custom module but i'm afraid i dont have experience with that either.
@@AntonyCatdog this sounds like a problem better solved by using a physics object for the dummy and then spawning an emitter via blueprint on the physics collision, rather than just using niagara. or via a custom module as i mentioned above.
How do you kill particles on collision? I have rain falling inside houses it looks ridiculous.
if you're using CPU collision then theres an option to advance the aging rate, just set that to a very high number and it will work as a kill on collision.
@@tharlevfx Thanks for the quick response! I took the default third person structure and flipped one of its walls up into a ceiling. So, the particles should be treating the actor as a collision object. I cranked advanced aging up to 100,000,000 and I still have particles passing through my ceiling. It appears there are more falling outside than under the ceiling. It appears some particles are colliding whereas others are oddly passing through.
Paul717 are you using cpu or gpu particles because they collide differently? Have you tried the analytical planes rather than mesh collision? Sadly particle collisions aren’t perfect so you might just need a different solution.
@@tharlevfx I'm new to Niagara so a lot of this is stuff I'm not familiar with. I have requires persistent IDs enabled. Sim Target is set to CPUsim. Collision is set to CPUsim. CPU collision type is raytraced. Collision is enabled. I'm read the tool tip of CPU collision type and it appears raytraced is what I need cuz I need the rain drops to collide with a variety of objects such as buildings, terrain, water and the third person character. The analytical planes looks like it would be limited in that regards. I've been doing more research, and some of the things that might work is kill planes, onparticlecollide event, and particleshascollided. I just don't have enough experience to know how to implement these, yet.
@@Paul-hw7kc yeah unfortunately particle collisions probably just arent reliable enough for this use case. the easiest thing might be to expose a lifetime parameter to your system and then just manually place your fx so that the rain doesnt go through the building. dealing with Rain fx in games is quite a known complex thing i'm afraid.
If, like me, you came here to learn how to use Collision Events to spawn GPU particles this is NOT a tutorial for you. This tutorial only shows how to use CPU particles in collision context.
It’s not possible to use collision events with gpu particles due to the nature of how the gpu works I’m afraid
@@tharlevfx Absolutely agreed. Just the title of the video could be a bit better. What I saw in a video titled "GPU Particles and Collision Events" wasn't what I was expecting.
@@YandWandA ah I see - I guess it’s two topics in one video, I can see how that could be misleading
@@tharlevfx That being said, credit where credit's due. Very good video overall! I ended up giving a thumbs down, due to only finding out at the very end of the video that I didn't find the solution I was looking for. In hindsight though, I feel I overreacted, so would rectify it.
Very helpful video!
Quick question: How can I use the collision event of a CPU particles emitter inside BP to make any sort of action on colliding and not just other emitter responses to the collision?
I hope it was clear and thanks again
Idan Ben-moshe I’ve not tried it with niagara but you definitely used to be able to create blueprint events from cascade particles - I made a video about it
Is it possible to make cpu particles collide with different emitter's particles, colliding particles mid air?
Sadly not, collisions between particles would be too expensive for real-time. You could try making a blueprint that spawns lots of little physics meshes but that might be expensive on the frame rate
@@tharlevfx Gotcha, thank you for the quick reply.
How about emitting invisible physics meshes with collision enable sprite emitter in the same systems, do you think the two systems in front of each other will simulate collision like effects? Or would only the meshes collide while the sprites go through? Thx
@@idanben-moshe1317 yeah I don’t think that works either I’m afraid. What type of effect are you trying to replicate?
@@tharlevfx I'm trying to make wo flamethrowers flames colliding, I have a great sprite emitting particle system that collides with the world, good fire spreading effects on collision with meshes or skeletal meah.. . But when fire meets fire I want them to collide in the middle. I hope my imagination came through
@@idanben-moshe1317 so I would maybe try having an invisible collision mesh the same size and shape and as the flames and then line or sphere trace forwards the same size and shape again - if the trace hits the collision then spawn a new effect for the flame collision, maybe shortening the lifetime of the two flamethrowers appropriately
Hi thank you for the great video. What would be the most effective way to kill particles as soon as they collide with meshes in your world? Like rain hitting a roof or ground. The moment they touch they get nuked. TY :-) Also is it possible to create "hold out" volumes, volumes in the middle of your world where you DONT want particles to spawn or enter or pass through.
In niagara there’s a kill module and a hascollided property - if you connect them then once they collide the particles will be killed instantly. You could also use this to definite a volume where particles are killed with a little bit of math
@@tharlevfx TY very much!