The RBD Constraint Properties node provides functionality similar to the parameters on the RBD Material Fracture node’s Constraints tab. You can use this as a convenient interface to edit values in the constraint network if you want to do more complex custom constraints. There are parameters to control plasticity in terms of stretching as well as the angle between the two objects in degrees where plasticity starts to take effect. This is useful for bending and breaking effects, where you want things to bend and hold their shape.
In addition to the RBD Constraint Properties node, there’s also an RBD Deform Pieces node, which handles bending your high-res geometry for metal-like deformations. This node looks at the constraints to see which pieces are still together. For pieces that are still together, it will use the neighboring pieces to create some smooth bending and deformation. Where constraints have broken off, it will start to tear away pieces from each other.
The Boundary Connection dropdown is important to determine what the boundaries between the pieces are and which pieces should tear off. The default is to use Constraints, which builds clusters of proxy geometry points between pieces that are connected via their constraints. Geometry pieces will only be deformed by proxy geometry points with a matching name attribute and proxy pieces' points within the same cluster. You can also change this to Cluster Attribute, which uses an attribute to determine clusters of proxy geometry points to be used to deform the geometry. Geometry pieces will only be deformed by proxy geometry points with a matching attribute value. You would typically change this to Cluster Attribute if you have a lot more proxy pieces than high-res pieces.