Create a Rigid Set from Multiple Objects

When you work with simulations that rely on numerous objects in the solve, for example, a wall made of thousands of bricks, it can significantly affect the performance of the simulation. Additionally, it can be tedious to select each object in the Outliner. In these cases, it is best to create a Rigid Set that comprises all of the Rigid Body objects included in the solve.

To create a Rigid Set from multiple objects:

1. Open the Outliner and Shift-select all the objects or groups you want to include in the solve. If you select a group, all non-intermediate mesh shapes found under the group are added as a rigid body
   
2. Go to Bullet > Create Rigid Set > . Creating a Set groups all the selected objects so you can select them quickly in the Outliner.
   Note If you run the Create Rigid Set from the Bullet menu with a single group node selected, it can use the name of the group node + "set". If a node already has that name, Bullet tries {objectName} + "set" + 1 and so on, until it finds a unique name. if you use multiple selection, it will fail if you do not provide a unique name.
3. Set a Name for your collection of objects, and choose Create Input Set and/or Create Output Mesh, See Bullet > Rigid Sets for more information on these settings.
   
4. With the Set still selected, go to Maya Display menu and selectNo Geometry. This reduces visual clutter and improves performance because the processor does not have to animate the geometry as well.
   Note Normal values and UV values are transferred but not materials or shaders. You can also use the Debug Draw option found on the bullet Solver. See Debug Draw.
   
5. The output mesh is used to visualize the simulation.

   You can also export a mesh shape using an Alembic cache, which can reduces a 50 000-object scene into one single large mesh, although you need to manually reconnect the materials and shaders. See Alembic Caches for more information.

You can edit the Bullet physics attributes for the rigid set in the Attribute Editor by locating the associated Initial Shate node which is found under the Bullet Solver Shape node in the Outliner.

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