Ember (Alpha v001) comes with two main objects that you will be using to generate ember fields. I’m going to give a brief rundown of them to speed up your access to the goodness.
[size=150]SIM Ember[/size]
This helper object is found in the Ember category of the Helpers page on the create tab. You can create it faster by adding a Create SIM Ember MacroScript to your User Interface. The Macros are located in the “Thinkbox” category.
SIM EMber is a time-dependent field that is most similar to PFlow or FumeFX at this point. It has two Ember flows within it and a variety of controls for the region of interest, the level of detail, and for visualizing the field.
The main idea behind it is that there is an initial ember fields expression that sets the object’s field values before the simulation starts and there is an ember field expression that updates the values “per-step”. When scrubbing the time slider, the object will run its “per-step” expressions in a loop until it reaches the Max slider time. Currently the simulation is not reset when scrubbing backwards. It is only reset when the slider is positioned at the beginning time (hard-coded to frame 0 at the moment) so any changes to the expression or object’s parameters will not be seen by the simulation until resetting the timeslider.
After executing each expression, the field values are cached to a grid, or staggered grid for Velocity, (if the “Discretize” options is selected) so they can be reused as InputChannel nodes when the expression is run to advance the time. If a solver is selected the Velocity grid is modified by the solver (to make it act like a fluid perhaps). The solvers are built-in and currently (Alpha v001) the only options are None (ie. no velocity changes are done) and FFT Solver (ie. A fast fluid solver that doesn’t support occlusion objects).
Before each “per-step” expression is executed all the fields are advected (ie. moved around) by the Velocity channel. This is currently (Alpha v001) not possible to disable.
In summary a SIM Ember does this:
[]Assigns its fields an initial value by running the Initial Expression.[/]
[]When updated to frame F, it will run the Per-Step Expression at least F times updating the internally stored fields each time according to the expression and several other built-in operations:[/]
[list=a][]All fields are advected (ie. moved) by the Velocity field before each application of the Per-Step Expression.[/]
[]The Per-Step expression is executed updating the advected fields (perhaps adding more density to a region, or applying forces to add velocity to an area, etc.)[/]
[]All fields are [optionally] saved to a grid AFTER each application of the Per-Step Expression.[/]
[]The Velocity field is [optionally] adjusted by the chosen solver (probably to make it act more fluid-like)[/]
[]Once we have reached frame F, the fields are made available to the rest of the system to be used by PRT Ember for generating particles, or by Ember Follow in PFlow for moving particles around. And other seeeecret things.[/]
[/list:o]
[size=150]PRT Ember[/size]
This object uses a procedural ember expression to generate Krakatoa particles within a region. The field expression MUST specify a Density channel in order to describe where particles exist. All other PRT channels can be optionally generated (ex. Velocity, Color, etc.). A PRT Ember is not time dependent, so it acts a lot more like a PRT Volume with a Magma modifier on top, except that it has access to a bunch of fancy new Ember nodes.
A PRT Ember can access the results of a SIM Ember (or FumeFx, PhoenixFD, or a 3ds Max Force Field) using the InputField node which points at the scene object you want and spits out its channels.
[Edit:] You will need the latest Krakatoa beta in order to render PRT Ember. That’s at least Krakatoa MX 2.1.2.47756 available here. Note that this build of Krakatoa does not support Ember as source for Krakatoa Atmospheric effect. An updated build that solves this will be posted later.
The PRT Ember object can be found in the Krakatoa category of the Create>Geometry tab of 3ds Max, since it is the connection from Ember to Krakatoa.
You can create it faster by adding a Create PRT Ember MacroScript to your User Interface. The Macros are located in the “Thinkbox” category.
[size=150]Ember Follow (Particle Flow Operator)[/size]
This operator uses an Ember Field (currently only SIM Ember supported) to assign particle velocities. Its currently (Alpha v001) pretty straightforward.