fluid sim, but as particle drops only

[ttdww]

This may be more of a newbie question, however I'm trying to use Phoenix as a particle-only generator, where I'd like to generate a particle sim (emitting splash drops only - or whatever would do the same) and have them pile up on the floor, allowing collision with objects, however not dying off like splash drops do when they collide with objects. Normally the drops would die to reform into liquid however I need to keep them as drops and deflect off each other.

Basically imagine the equivalent of a fluid sim however without the metaballing of the liquid - just keeping them as separate drops, but still able to fill a volume.

How could this be done? Or is there another way to do it in Phoenix? Apologies if there is an obvious answer. Thanks!

[Ivaylo Katev]

with the official build you can't achieve this, because the splash particles are disappearing when collide, but if you have nightly build you can use the liquid itself, if the generated particles have low density, they will not merge in the air, but will remain on the floor and merge when the quality is enough.
my suggestion is to use injecting non solid source, the geometry source produces solid water stream, the brush source works in binary mode in the flip solver, because there is no "bitmap" to draw over.

[ttdww]

hi Ivaylo, thanks I'll try that. could you explain the last sentence - I'm unsure what is mean't by "the brush source works in binary mode in the flip solver, because there is no "bitmap" to draw over". Thanks!

[Ivaylo Katev]

the brush source is designed to work on grid, where you can modify the grid values gradually.
the particles are existing or not, there is no intermediate possibility, that's why the brush source is working in binary mode when is used with the flip solver.

[ttdww]

i've tried to set up a scene (link below) where the drops are injected from a non-solid, but they are still disappearing when they impact an object and the floor of the container. it also looks like i'm only getting drops at the edges of the liquid, not filling the liquid completely.

would it be possible to show the changes needed to have the drops not disappear and be the whole volume of the liquid?

i'm not sure how to set up the scene to meet the criteria "you can use the liquid itself, if the generated particles have low density, they will not merge in the air, but will remain on the floor and merge when the quality is enough", so i'm guessing some things are not set up correctly. thanks!

http://vfxfactory.com/Rnd_d_v002.zip

[Ivaylo Katev]

see the attachment, it demonstrates the setup.
note that it requires nightly build, the effect you need is not achievable with the official build

[ttdww]

thanks Ivaylo! i'm using the nightly builds.

that works great for the emission - looks like what we want at the start, however the liquid is reforming when it impacts and collects.

i'm trying to have it remain as separate drops that deflect off each other and maintain a volume but do not form a fluid mesh. so imagine a phoenix fluid sim but without the metaballing effect of the liquid - where each FLIP particle remains as a separate sphere. can that be done?

[Ivaylo Katev]

you can use different rendering approach, render the particles not the mesh

[ttdww]

i think i got it working. after simming, create a foam object and choose the liquid event, adjust particle scale. set the liquid box to not renderable. is that the correct method? thanks again!

[Ivaylo Katev]

yes, this is enough if you need simple water material for the rendering, not milk or blood

[ttdww]

actually on that topic.. how would i force a foam object to use another material other than it's built in parameters? i thought i read somewhere that someone pulled it off. thx Ivaylo!

[ttdww]

also how might i fade and/or change the size of foam over it's age using a texture? i have the sim foam age channel saved with the sim. just not clear how to utilize it at render time. thanks!

[Ivaylo Katev]

there is no way, the foam is not a geometry object , and even in geometry mode it uses the foam shader.
to draw the particles with another material you have to turn them into mesh using metaballs or another particle mesher.
to change the size using the particle age use the "PA" option in front ofthe size multiplier. when this button is on, the size multiplier animation is evaluated using the particle age

[ttdww]

thanks for the info. so in your last comment about the PA option, do i then animate the size from say frame 0 to 30 for values of 2 to 0 for example, and then for each particle born they will scale down from size 2 to 0 over 30 frames for each particle age?

[Ivaylo Katev]

yes, exactly.