What's New in Simulation and Effects in Maya 2017 Update 2

Bifröst Foam

When generating a mesh from foam, the bifrostVelocity channel is now exported as a color set.

In addition, there are new attributes for controlling Bifröst foam.

Micro Vortices

Creates fine structure in the foam when it is emitted by pushing the particles using vortices that are a few voxels in size.

Emit Motion Streak

Randomizes the particle positions along the velocity vector when they are emitted. Higher values may help to reduce banding but also may result in a noisier appearance.

Boundary Drag

Applies a drag force that is strongest where foam particles are not colliding with each other and weakest where they are. This can help to break up clumps of foam above the liquid surface because particles on the outside of the clump experience more drag than particles on the inside. For this attribute to be effective, set Preserve Volume to a non-zero value and make sure Point Radius is large enough for particles to collide.

Air Turbulence

The magnitude of a turbulence field that is applied to the air velocity, and affects particles above the liquid surface. Note that this controls the speed of the air, while Air Drag and Boundary Drag control how strongly particles are affected by the air velocity based on their density.

Air Turbulence Frequency

The granularity of the turbulence. Higher values produce smaller, denser vortices.

Air Turbulence Speed

The rate at which the turbulence pattern evolves over time.

Bifröst Kill Field improvements

You no longer need to use multiple Kill Fields to delete particles based on a combination of criteria. You can now activate any combination of Boundary, Lifespan, and Droplets modes on the same Kill Field.

You can also use any polygon mesh to define the Kill Field boundary, as an alternative to using one of the available implicit shapes. To do so, first select both the mesh and the main Bifröst container or shape, and then select Bifrost > (Add) Kill Field.

Cache Bifröst meshes

You can cache the mesh output of a Bifröst simulation as per-frame BIF files. To do so, create a user cache for the simulation (see Create a Bifröst user cache) and make sure that Cache Elements: Mesh is enabled in the Bifrost Compute and Cache Options window.

BOSS

There is a new version of the Bifröst Ocean Simulation System. Among many other changes and fixes, please note in particular:

• You can use BOSS to generate maps representing foam on top of an ocean surface. See Generate BOSS foam maps.
• For spectral solvers, the behavior of the Patch Size X (m) and Patch Size Z (m) attributes has changed. They still control the extent of ocean surface that is simulated, but now if the simulated patch is smaller than the mesh domain, it results in either undeformed or repeated regions depending on the Periodic attribute. If the simulated patch is larger than the mesh domain, then the deformation represents only a portion of the area that is simulated and optionally cached — you can transform the input mesh within the patch to reveal other regions if desired.

  Previously, the patch was stretched or squashed to fit the domain. To recover the old behavior, you can use Space Scale to scale the patch to fit the domain.

• When applying a BOSS cache as a displacement map, you no longer need to flip the image in Z by adjusting the Repeat UV in the place2dTexture node.
• The Cache Continuously option continuously writes and overwrites cache files for solvers as you adjust settings and play back.
• You can now use the tokens <project>, <scene>, <object>, <influence>, <frame>, and <f> as tokens for defining cache folders and names. The csh-style ${token_name} format is still supported.