This tool fills an object loosely with grains and creates constraints to hold it together into one object. It is similar to Dry Sand and Wet Sand. However, instead of filling an object with unconstrained independent grains, all of the grains are constrained to each other to maintain the distance between each particle. It creates actual bonds that either always stay together, or can be torn apart.

The controls in the Explicit Constrains section of the POP Grains node can be used to change the behavior of the grains. The default result is a soft and bouncy object that does not break apart. However, by turning on the Break Constraints checkbox and setting a Break Threshold, this tool can be use to create wet sand objects that break apart when forces are applied, like a sand castle.

This tool can be thought of as a simple FEM solver. It results in solid-like behavior because there are no collisions between particles since they are all right next to each other and constrained. Like FEM, you can use Granular Solid to simulation disintegrating soft bodies. Granular Solid may run faster, but have less realistic, more bouncy results.

For more information, see PBD vs FEM.

1. Select the geometry object to convert to a Granular Solid object.

2. Click the Granular Solid tool on the Grains tab.

The following are a couple of examples of things you can use the Granular Solid tool for.

The following parameters in the Explicit Constraints section of the POP Grains node will allow you to change the behavior of the grains.