Resolved Drawing smooth weapon slashes

I'm adding sweeping visual effects to the swords in my game. I'm using ribbons, and they work pretty well -- but for very fast animations, they get very jerky.

I figure I could fix this with the power of splines. I've grabbed the

com.unity.splines

package, and I can create nice smooth paths from the fast swings -- but I'm stuck on the part where I turn that into a visual effect!

I'm going to have to generate several particles per frame and provide the position for each one. I think I'm just going to add four Vector3 parameters to the visual effect and store four positions in those...but that doesn't feel very scalable. If I want to smooth further (maybe adding a variable number of points depending on speed), I'll have to add even more parameters!

Any thoughts on how to make this simpler?

 

Some updates: I'm having trouble drawing several particles per update. I tried setting a Vector3 property and using that as the position in the "Initialize Particle Strip" block:



(I'm a little confused as to why I can't just use Set Position, but I guess it's because it needs to set the position at the correct index?)

It works normally if I rig it up like this:



...but if I try to hook it up to an event that I call several times per update, I get nothing at all.



Maybe I'm just completely misusing things here?

 

Okay, one last post for the moment -- I found this thread, and I successfully got it working with individual particles.

I send an event several times per frame, with a different position value attached each time. That winds up creating several particles in several different places simultaneously!

I cannot, however, work out how to do the same thing for a particle strip.

 

Thanks! I actually got the strip positions working -- I'm a little unclear on what was wrong, exactly; I think I was misunderstanding how to use Direct Link. Here's how it's looking now...



I'm just working on the orientation now. I need to get it to line up with the long axis of the sword. I'm unclear on how to do this: I'm guessing I need to include an orientation with each event, but I do not know how to do that!

I attached a package with a demo of how it's behaving. There's some cruft (i can't remember why i decided to name an attribute "blorp"), but it should be straightforward enough

I tested it in 2022.2.9f1 using the HDRP. The "Line" prefab will spawn an object called "Line's Target" and then draw particles based on the target's position.

I did it that way so that the spline gizmos would line up correctly; leaving it on the weapon meant that it would fly all over the place.

Note that it didn't work on the first try...but it started working after I open the picker for the shader on the "Output Particle Quad" node. It might've just been a coincidence! Just something to try if it's misbehaving

So, in short, my original problem seems to be fixed, but I'd appreciate some pointers with the orientation (and for Direct Link in general!)

 

Got it! That makes a lot of sense, thank you -- I was pretty fuzzy on how the orientation worked, and I think I see what's going on now