Reference/Release Notes/2.91/Physics

Rigid Bodies

 * Support for "Compound Shape" collisions.


 * You now can combine multiple primitive shapes into a concave shape. For instance, to a chain link collision shape you can use multiple wire edge child objects:




 * Doing it like this makes the simulation run a lot faster than if using the "mesh" collision shape. It is also in most cases a lot more stable.

Fluid

 * Improved obstacle handling:
 * Advanced obstacle-liquid interaction (UI toggle "Fractional Obstacles") has been improved
 * Particles now flow more smoothly over inclined obstacles
 * For even finer control, there is a new option "Obstacle Distance" which defines the distance that liquid will maintain towards any obstacle.


 * OpenVDB cache:
 * In `.vdb` format, liquid simulations can now be saved with Full (32 bit), Half (16 bit) or Mini (mix of 8 bit and 16 bit) precision
 * Especially scenes with large amounts of liquid particles benefit from smaller cache file sizes as viewport performance increases significantly
 * E.g. beach scene from above (~300.000 liquid particles): Before 4.1 GB, now (Mini format) 1.26 GB

     
 * Improved "Viewport Display" options:
 * Note: This feature is aimed at developers and when a deeper inspection of the simulation is required.
 * It is now possible to visualize liquid simulations grids (before only smoke).
 * Vector display options have been improved: Velocities and forces can now be viewed per axis (MAC visualization).
 * An option to display gridlines for the underlying simulation grid has been added.
 * Cell coloring options have been added: Obstacle, fluid and empty cells can be identified in the underlying grid.
 * In-depth report: Liquid Simulation Display Options