When working with simulations, set your preferences to play back every frame.
Understanding Bifrost - Simulation Scale
These are the unit assumptions that Bifrost makes:
scene scale units: meter
Gravity = 9.8 meters per second squared
Liquid Density = 1000 kg per cubic meter
Surface Tension = .072 kg per second squared
input temperatures as celsius, and bifrost converts that to kelvin
Regardless of Maya's scene scale, Bifrost always assumes that the units are meters. Ideally, you would model all geometry in meters and work with a scene scale of meters, because then you can use Bifrost's default values for everything. However, often you'll have a scene that's already setup with different scene units, such as centimeters, and instead of changing the scale of all geometry it might be easier to cheat the values in Bifrost to trick it into thinking the scene is at the correct scale of meters. Here are the attributes to adjust.
For each attribute, let d be its default value and f be the factor of your geometry's intended units relative to meters.
Here are the factors f for various user scales:
mm = .001
cm = .01
inch = .0254
foot = .3048
yard = .9144
The names of the attributes that need to be adjusted are listed below, along with each one's formula for making the adjustment (the formula involves the default value d and factor f). For example, in the case of gravity, the formula to determine the Gravity Magnitude's value in order to correct for the given user scale is d/f. So if the user scale is cm then the value of Gravity Magnitude should be its default divided by .01, or 9.8 divided by .01 or 980.
Scene scale
Bifrost ignores Maya's scene scale, so don't bother changing this.
Windows -> Settings/Preferences -> Preferences -> Settings -> Working Units -> Linear
Gravity
In the attribute editor for bifrostLiquidPropertiesContainer<x>, expand the Properties section, expand the "Solver Properties" subsection, and adjust the value for Gravity Magnitude.
Gravity Magnitude = d/f
For example, the value for a user scale of cm is 980.
Liquid Density
In the attribute editor for bifrostEmitterProps<x>, go to the emitterProps<x> tab, expand the "Emission" section, expand the "Physical Attributes" subsection, and adjust the value for Density.
Density = d(f cubed)
For example, the value for a user scale of cm is .001.
Surface Tension
In the attribute editor for bifrostLiquidPropertiesContainer<x>, expand the Properties section and expand the "Surface Tension" subsection. The Surface Tension attribute lives here, but it's disabled by default so you don't need to adjust it?
In some cases you might need to adjust the adaptivity settings to account for user scale.
Transport
In the attribute editor for bifrostLiquidPropertiesContainer<x>, expand the Properties section, expand the "Adaptivity" subsection, expand the "Transport" subsection, and adjust the value for Transport Step Adaptivity? Increasing this value increases accuracy?
Time Stepping
In the attribute editor for bifrostLiquidPropertiesContainer<x>, expand the Properties section, expand the "Adaptivity" subsection, expand the "Time Stepping" subsection, and adjust the value for Time Step Adaptivity? Increasing this value increases accuracy?
In some cases you might need to adjust the voxel resolution settings to account for user scale.
Master Voxel Size
The master voxel size controls the resolution or perhaps density of the sim. The smaller the value, the more particles will be generated within a given volume.
In the attribute editor for bifrostLiquidPropertiesContainer<x>, expand the Properties section, expand the Resolution subsection, and adjust the value for Master Voxel Size. The default is .5 meters.
If you're using a motion field, then you might have to adjust that field's magnitude to work with your scene scale.
In the Attribute Editor for bifrostMotionField<x>, go to the bifrostMotionFieldContainer<x> tab, expand the "Motion Field Properties" section, and adjust the value for Magnitude.
Magnitude = d(1/f)
For example, the value for a user scale of cm is 100.
Creating Water in Maya 2015 with Bifrost
Make a container/basin to hold the water by creating a box and putting a hole in it.
Make a small box and place it over the container/basin. This will be the faucet that water is emitted from. Give the box 5 subdivisions on each side.
With the faucet selected, choose the FX menu set, and choose "Bifrost Fluids -> Liquid".
Select liquid<x> (under bifrostLiquid<x>), shift-select the container/basin object, and choose "Bifrost Fluids -> Collider". This will prevent the water from running through the container.
Set frame range to 200, go to frame 1, and click play. Water is simulated on each frame of the frame range. This will take a while. Because of the default settings that include gravity, the water will fall from the faucet and splash into the container.
I think you might need to stop the sim at the last frame and cache it, because if you then try to skip through frames in the timeline out of order then it blows away the sim?
When the simulation is done calculating, cache it so it doesn't disappear the next you launch maya. Select liquid1 and choose for the options box for "Bifrost Fluids -> Compute and Cache to Disk":
Cache directory: <project>/cache/bifrost/<scene name or sim name>/
Cache name: <name of sim>
Cache format: bif
Compression format: Simple
Cache Elements: Sim
Cache time range: whatever's appropriate
Write Mode: Write All
Click Create. You can now scrub through the timeline to play the cached sim.
The cache is connected to the sim in the bifrostLiquidProperties<x> node. In the attribute editor, expand the Caching section, and then expand the "Liquid Cache" and "Solid Cache" subsections. The paths to the cache are listed here. A value of 1 Cache Control is read mode, and 2 is write mode. Cache Control should be in read mode while playing back the sim.
If you want to edit the sim and recache it, disable the LIquid and Solid caches (described above), go to frame 1 in the timeline, and click the play button to re-sim. Once each frame has been calculated, click Stop and choose "Bifrost Fluids -> Compute and Cache to Disk". The Liquid and Solid caches will automatically be renabled, pointing to the path to the new cache.
When the bifrost sim is created, a bifrostLiquidMaterial<x>SG shader network is automatically assigned to it, with the material aiStandardSurface<x>.
Add HDRI lighting using an arnold dome light.
Create realistic materials for any collision objects so the water has something reasonable to reflect.
Render in Arnold.
Create a Water Splash in Maya 2015 with Bifrost
Make a container/basin to hold the water by creating a box and putting a hole in it.
Make a fluid object that will act as the volume of bifrost water by making a poly box that fits closely inside the container/basin, and doesn't quite go up to the top lip of the basin.
With the fluid object selected, choose the FX menu set, and choose "Bifrost Fluids -> Liquid".
Select liquid<x> (under bifrostLiquid<x>), shift-select the container/basin object, and choose "Bifrost Fluids -> Collider". This will prevent the water from running through the container/basin.
Make a poly sphere (ball) to use as the object that drops into the water to make a splash. Place the ball above the water, close to it.
Select liquid<x>, shift-select the ball, and choose "Bifrost Fluids -> Collider". This will allow the ball to splash the water.
Set the frame range to about 50 frames or so.
Animate the ball over the first 10 or so frames so that it drops into the water and is completely submerged.
Go to frame 1 and click play. Water is simulated on each frame of the frame range. This will take a while. The ball drops into the water and creates a splash.
I think you might need to stop the sim at the last frame and cache it, because if you then try to skip through frames in the timeline out of order then it blows away the sim?
When the simulation is done calculating, cache it so it doesn't disappear the next you launch maya. Select liquid<x> and choose for the options box for "Bifrost Fluids -> Compute and Cache to Disk":
Cache directory: <project>/cache/bifrost/<scene name or sim name>/
Cache name: <name of sim>
Cache format: bif
Compression format: Simple
Cache Elements: Sim
Cache time range: whatever's appropriate
Write Mode: Write All
Click Create. You can now scrub through the timeline to play the cached sim.
Hide the fluid object so it doesn't obscure the view of the water.
Create geo for the emitter.
With the emitter object selected, choose the FX menu set, and choose "Bifrost Fluids -> Liquid".
In the Attribute Editor for bifrostEmitterProps1<x>, go to the emitterProps<x> tab, expand the Properties section, and check "Continuous Emission".
Add a motion field to the existing liquid/emitter.
In the Attribute Editor for bifrostMotionField<x>, go to the bifrostMotionFieldContainer<x> tab, expand the "Motion Field Properties" section, and expand the "Field Direction" subsection.
Set the direction to 0,1,0 to point the force upward.
I think that a boundary control needs to be setup so that the sim doesn't create a new chunk of water on every frame? Select the bifrostEmitterProps<x> node and go to the Boundary Controls section in the attr editor. Enable Boundary, set it to Box, and interactively place the box in the viewport to occupy on the space where you want the initial volume of water to be created?