Abstract: Implementations relate to methods, systems, and computer-readable media to automatically perform rigging of physics-based three-dimensional objects. In some implementations, the method may include obtaining a 3D mesh of a 3D object, segmenting the 3D mesh into two or more sub-meshes, wherein each sub-mesh corresponds to a respective part of the 3D object, determining a constraint graph for the 3D object using a transformer model, wherein the two or more sub-meshes are provided as input to the transformer model, and wherein the constraint graph defines a set of joints such that each joint defines constraints on motion of respective pairs of the parts of the 3D object, and calculating a plurality of parameters for the constraint graph based on one or more objective functions, wherein the sub-meshes, the constraint graph, and the plurality of parameters are usable to simulate motion of the 3D object in a virtual environment.

Abstract: Some implementations relate to providing adaptive, distributed simulation of fluids with rigid body coupling. According to one aspect, a method simulates, with a coarse resolution on one or more server devices, a global flow field for a fluid within a virtual environment. The method determines regions within the grid to obtain additional detail for, based on the presence of one or more rigid objects within the virtual environment. For each region, the computer-implemented method: assigns client device(s) to the region; sends fluid simulation data pertaining to the region to the client devices; and receives refined fluid simulation data for the region from the client devices. The method replaces the fluid simulation data in the global fluid simulation pertaining to the regions with the refined fluid simulation data for the regions. The method then updates the global flow field for the fluid in real time based on the simulation data.

Abstract: Some implementations relate to methods, systems, and computer-readable media for determining updated states of rigid body objects. In some implementations, the method includes receiving a model representation of rigid body objects, receiving an input state of the rigid body objects, determining that a relative velocity meets a threshold velocity, responsive to determining that a first rigid body object and a second rigid body object are in contact and that the relative velocity meets the threshold velocity, constructing a merged representation that represents the first rigid body object and the second rigid body object, applying a solver based on the input state and the merged representation to obtain an updated state for the first rigid body object and the second rigid body object, and causing the first rigid body object and the second rigid body object in the updated state to be displayed within a virtual environment.

Abstract: Some implementations relate to methods, systems, and computer-readable media to provide scalable soft body locomotion/animation for a virtual experience, such as a three-dimensional (3D) environment. In some implementations, the method includes building a control space having information representative of forces corresponding to natural movement of the soft body, wherein the soft body is part of a virtual environment, coupling the control space and a physical space to define a controller pipeline that performs animation of the soft body, performing the animation of the soft body using the controller pipeline, and causing the animation of the soft body to be displayed in a user interface of the virtual environment. Building the control space may comprise simulating the forces corresponding to the natural movement of the soft body by solving an elastodynamic optimization problem using auxiliary variables as degrees of freedom.

Abstract: Methods and systems for executing a simulation of a multibody system are described herein. In one broad aspect, there is provided a computer-implemented method for executing a simulation of a multibody system, where a physics-based simulator is used to simulate the multibody system by: partitioning the multibody system into a plurality of subsystems, the multibody system comprising bilateral and unilateral constraints, and a set of interfaces that couple at least two of the subsystems is defined; at each of a plurality of time steps, employing a Schur complement method to compute an effective mass at each interface of the set of interfaces, and solving each of the plurality of subsystems to obtain a plurality of internal impulses.

Abstract: Methods of and systems for executing a simulation of a constrained multi-body system. The method comprises, using a physics engine, simulating the constrained multi-body system, wherein: the constrained multi-body system comprises articulated constraints, the articulated constraints are associated with a geometric stiffness matrix; the geometric stiffness matrix defining a geometric stiffness; a diagonal approximation of the geometric stiffness matrix is generated; and the diagonal approximation is used as part of a stability analysis in which damping is automatically adjusted so that the damping stabilizes the simulation of the constrained multi-body system.