liquid emitter may intersect? / how to find out speed of indivisual particles?

[Alexx31]

Hello,
here are again two basic questions

1. Does it matter, if an emitter is partially intersecting a solid ("collider")?
I have set the solid geometry to kill everything inside. Sometimes I want the emitter to be as close as possible to a surface, so it can easily happen, that it intersects.

2. Can I see the speed of individual particles?
When settings were based on speed (the threshold for the birth of splashes for example), it's hard to say, which part of water has which speed.
All I can see in the info window is a general speed info of min and max.

Thanks

[Svetlin.Nikolov]

Hey,

1. It's not a problem for an emitter to be overlapped by a solid - liquid will not be able to live inside solids.

2. Not really possible to see individual velocities, but I have it in mind - for now you can only color-code the particles - by default their color is already scaled by their speed, so faster particles are white and slower are the color chosen for the particle system.

Cheers!

[Alexx31]

Okay Color code? Can I define a color for a certain speed? If I want to know which are faster than 3m/sec?

[Svetlin.Nikolov]

Ah, better check the info here: https://docs.chaos.com/display/PHX4MAX/Liquid+Preview, especially the info on the Scale Color By and the Scale Max options.

[Alexx31]

Thanks, about UNITS:
What's confusing to me and can lead to many effectless simulations: That there are never units explained in phoenix and even when I go through the manual, it is only sometimes clear.
Especially as they are not all the same (percentage, voxels, meters, relation to other voxels)

It would be great to implement a simple tool help, that explains at least the unit.

I'm searching what is meant by the threshold of splashes? is it voxels per frame? or per second?
And often is not clear to me, what's the range of an attribute, some can go into millions, some are between 0 and 1...

[Svetlin.Nikolov]

Ouch, this hurts I've tried very hard to improve the old docs over the years and add info about what units every option is in everywhere, so saying that units are never explained makes me think I should drop coding and revisit the docs once more...

So all options that are in world units already have the corresponding 3ds Max control that displays the unit in the spinner - e.g. meters, cm, inches, etc.

Other options, such as percentages, have (%) next to their names, and all the rest should be explained in the docs. UNLESS they are really unitless, such as multipliers between 0-1, or such as the Splash Birth Condition which is a combination of a bunch of factors that really don't matter and shouldn't be explained - the curvature of the liquid surface, velocity and acceleration, etc. Just trust us that the lower the threshold, the more splashes will be born If you are looking for units in order to try and predict what value you need to dial in so you get exactly X splash particles - this is impossible to predict, so don't try it, really. Just iterate a couple times, even using resimulation only of the Splashes which should be quick and also by reducing the width or height of the grid so the voxel size remains the same and the birth conditions are intact.

Cheers!

[Alexx31]

I understand and fully feel with you, Svetlin

But one example:
By Free fly goes from 0 to 1
Threshold from 0 to 100
(no explanation, no units)

Here would a tooltip help, at least telling the range, otherwise you come into traps if you are new to Phoenix.
(and ideally I would also set every abstract 0-1 slider to percentage, to have it consistently. but that's just my thought)

[Svetlin.Nikolov]

I agree, ideally all options should be either between 0-1, or in units, but this is not possible in reality.

For example, take the Steps Per Frame option - by default you have 1 step per frame, and if you have fast moving fluid or geometries, you must increase it, so it can go up to 5, 10, 20... there is no upper limit, so this option has neither units, nor can be limited between some minimum and maximum, such as 0-1