Yade2

Overview:

Scene
 [field, field, ...]
 engines (1)
Field:
 [node, node, ...]
 [nodeData, nodeData, ...] (2)
Node:
 position, orientation
 constraint*
 DynState*

DemField: Field
 [particle, particle, ...]
 [contact, contact, ...] (3)
Particle:
 Material*
 Shape:
  Bound
  [node,node,...]
 contacts: {otherId1: Contact*, otherId2: Contact*, ...}
Contact:
 particleA*, particleB*
 CGeom*, CPhys*, CData* (3)
CGeom:
 node
CPhys:
 force, torque (4)
CData: /* arbitrary */