Foam particles cutoff at simulator edge - why?

[hardrock_ram]

Take a look at the image below. I don`t understand why the foam particles are cutoff so abruptly at the edge of the simulator box. As I understand the foam should live on for 10 seconds outside the box, and some of the foam particles has done that. Why is there a cutoff for most of the particles? Appreciate any help

EDIT: The units are in cm and the boat is in the ballpark of 60 meters long. It travels at about 28 knots in this scene. The foam is made with resim on top of an ordinary liquid.

[Svetlin.Nikolov]

Hi hardrock_ram,

The Outside Life parameter is a trap that we have to change - currently what it says is "if the particle exits the grid and its Total age by now is more than X seconds, then kill it". This is the reason for the abrupt cut-off. We have to think about how to fix this behavior.

Cheers!

[Ivaylo Katev]

yes, this is a big problem. let me explain more
to make the outside life behavior as expected, we should add an additional channel containing the life of the particle outside the grid.
However, each additional channel consumes memory, that is important, we are trying to minimize it. Our solution is to kill the outside foam after it reaches certain age, that is apparently misleading the users, because some particles have this age before exiting the grid, and this produces the sudden drop of particle density on the border. For now, just set a bigger value, we will decide what to do with this trap.

[hardrock_ram]

I see Yeah, the text in the interface is a bit misleading ...
Thanks for the reply

[Neilg]

yes, this is a big problem. let me explain more
to make the outside life behavior as expected, we should add an additional channel containing the life of the particle outside the grid.
However, each additional channel consumes memory, that is important, we are trying to minimize it. Our solution is to kill the outside foam after it reaches certain age, that is apparently misleading the users, because some particles have this age before exiting the grid, and this produces the sudden drop of particle density on the border. For now, just set a bigger value, we will decide what to do with this trap.

Would you be able to have it reset the counter or only start counting if it hits the grid?

[Svetlin.Nikolov]

This would unfortunately compromise the particle age channel when used for other purposes. As Ivaylo said, another obvious alternative would be to dedicate a new particle channel specifically to tracking the exiting particles, which would consume additional memory. We would take the new channel approach only if we don't come up with other feasible alternatives, such as e.g. distance-based particle fade-out, etc.

[Ivaylo Katev]

or we can abandon the outside life concept and replace it with age limit + checkbox "ällow outside simulation"

[hardrock_ram]

Yeah, I myself think that the current arrangement is just fine, especially if it has advantages in saving space. The label has to be changed so the users knows what is actually going on, but other than that its fine really ...

[baro]

[QUOTE= ....For now, just set a bigger value....[/QUOTE]

how big this value could be?
I started with:

which gave:

I wanted it to look more like:


to be continued (due to # of pix limitation)

[baro]

so I increased the life values to:

and got this:

not too happy
bumped it higher:

still not quite what I was shooting for:

so, are those lives* in real seconds or are they sort of multipliers?
shall I try different combination of values or is there a way to fake the wake of my tanker to look more like the reference pix

thx in advance for the help
pl

[Svetlin.Nikolov]

Seems like something is stopping the foam from exiting the simulator. Can you try with 3.00.02 and if it's still not good, can you send the scene to Support so we can make sure this does not happen?

[baro]

re-did simulations with 3.00.02.
looks quite different. same frame 1000 I earlier posted example picture of, now look there is either less foam or if it is rendered in point mode (but it's not).



I extended the simulation to make sure foam has time to leave simulator and it does through the aft wall ,but I still think it does leave thought the sides.



I sent the scene to support if you would like to take a look.
biggest question is why render looks so different now. took me quite some trying to get the foam to look docent before 3.00.02

cheers
pl

[Svetlin.Nikolov]

Thanks! Will have a look, but before that I think I know what might be causing it - we did some changes related to the new V-Ray adaptive lights that caused problems with 3.00.02 + older versions of V-Ray. Would it be possible to grab a latest nightly where this is resolved for older V-Ray versions as well?

[baro]

as advised did new sim with 3.05.02 Nightly Build ID: 1701207158
render looks "normal", as before-v3.00.02


still, it looks like plenty of the foam dies off. there is so much foam at the bow which gradual thins out toward the stern and being it. seems the program is not very "respectful" of my settings:

again, my goal here is make it look like on the ref. pix in my previous posts, where the foam seems to live forever.

cheers
pl

[georgi.zhekov]

Do you have the Age exported for the particles?