3D faded trail?

[Krion]

Hi,

I was this gif on cgwiki's solver sop tutorial.

And I went wondering if leaving a trail like this would be possible in 3D, without a grid to transfer it to.

So I made a trail by merging the previous frame with input on in a solver and I tried a Wrangle with @Cd *= 0.95; This kinda worked.

 

But I'm sure there is a better way. Maybe in SOPs a nicer way? That would also kinda make it one geometry?

Or would someone need to transfer attributes to Volumes or something to do this? 

What is the best, most beautiful and most efficient way?

 

Would love to hear your thoughts.  

[char]

I'm guessing it would work with volumes as well, as it's quicker to set up fading density, right?

[Krion]

Curious how that would be done. When I search on volume trails I get a lot of tutorials for complex visuals with lot's of lines from velocity, not really what I imagine.

Can you maybe set up a simple hip file?  

Edited June 26, 2019 by OdForest

[char]

I'm guessing I'd be easier if you just used particles and mapped the normalized age attribute to be density and then re-fit it so particles born have high density and it's slowly decaying based on how old they get. I could maybe set a scene up till the weekend, bit busy at the moment.

[3dome]

maybe this can help

 

[Krion]

I certainly like something like that vex method, keeping it one geo.
Any chance of having that ‘motion blur’ move along the motion path with that method? Like a trail SOP does when on "preserve original"?

Here's a hip. curved like trail-questionmark-.hipnc

Edited June 29, 2019 by OdForest