It’s possible to use meshes instead of sprites for particle systems. What are the benefits of that?
In what ways could that be used? The only one I can think of is if a lot of 3D objects are supposed to move and that it would be jarring to only see them from one angle.
But surely there are more ways to use mesh particle effects. Does anyone have ideas?
One example I can give you is if you want to make a magical orb of some sort. You would use a mesh emitter with a sphere static mesh. It is simply another option for you to create this kind of effect. The advantage of using a mesh in this case, would be the fact that you can tweak how you want the orb to look by modifying the material in whatever ways you want instead of creating a SubUV flipbook or whatever else you would use otherwise. What you said is right, these 2 things are reasons why you’d want to use a mesh.
They’re very useful. Here’s a few things I use them for:
Mesh particles are treated like 3D objects and are not aligned to the camera (they can be if you want them too though)
Would emitting a mesh particle be lighter on performance than spawning a 3D object instead?
I’m curious about the mesh volumetric effects. Can you tell me more about that?
It’s not so much the meshes themselves but more the materials, kind of like the volumetric god-rays / light shafts that used to be in UDK (and I think still exist somewhere in UE4).
Mesh Particle would definitely be lighter on performance than a full static mesh component. For projectiles for example, the best approach is to have a base collision sphere then just a particle and (if you need it) audio component. There are some limitations, Mesh particles can only have one material for example - but you’d rarely need more for something like that.
For things like explosions where you have 3D rocks or debris, mesh particles will be considerably cheaper than spawning meshes.
Thanks for the info.
So, just having the possible of one material is lighter than having the possibility of several materials, even if it does unused? Or only when several materials are actually used? Or are you saying that a mesh particle material is lighter than a static mesh material?
Would it be possible to spawn several mesh particles, each with its own collision sphere, and then have each of them blow up when its collision sphere hits a surface?
Can mesh particles stick around? Say, if someone blows up a wall and this produces 3D rocks mesh particles, can those be made to stay for an arbitrarily long time?
The materials cost the same, but what I mean is it’s not possible to have multiple materials assigned to the same mesh with Particle Meshes - if you have a mesh with multiple material ID’s, it’ll just share the same material across all mat ID’s. I doubt anybodies ever going to need two materials for a bullet or shell or something though… or if they do they’re doing it wrong.
You can add collision to particles but it’s not advised since it’s expensive, it’s much more performant to use the primitive shapes for collision. You actually wouldn’t be able to access the particle collision events outside of the particle (in blueprint at least), so you wouldn’t be able to do a lot with it anyway.
And yeah, particles can stay around for a while. However it’s worth noting the particle collision has no ‘radius’ as such, it’s just a fixed point in space so objects will clip through the floor and that can break the effect if it’s for large objects. What you probably want to look at for blowing up walls and the like is destructible meshes. All this stuff can be found in Content Examples btw 
Yes, I’ve gone through the whole Content Examples but forgot that. There’s a lot to remember. The thing I remember most about particles is the GPU particles because I was quite impressed that my 5 year old ATI 6850 was able to handle it.
Let me make sure I get this right: Spawning particles would be cheaper than static meshes because particles would be likely to have fewer materials and have simpler collision shapes?
Also, nice stuff on your Youtube channel; I particularly liked the movement of the the hover tanks and projectiles.
The space game videos make me wonder if you’ve played Kerbal Space Program. If not, I think you’d like it even if its graphics are lacking. Or are you aiming to make a better looking version of KSP? That would be nice.