Nvidia Corporation

Nuttapong Chentanez

Miles Macklin

Matthias Mueller-Fischer

Matthias Heinz Muller-Fischer

Stefan Jeschke

Tae-Yong Kim

Matthias Müller-Fischer

Matthias Müller

Viktor Makoviichuk

Matthias Mueller Fischer

Apparatuses, systems, and techniques apply to a force-based (e.g., primal) formulation for object simulation. In at least one embodiment, updates to the force-based formulation is determined by solving for constraints that are to be satisfied when simulating rigid bodies (e.g., contact rich scenarios).

Methods of contact for simulation

A cable driving a large system such as cable driven machines, cable cars or tendons in a human or robot is typically modeled as a large number of small segments that are connected via joints. The two main difficulties with this model are satisfying the inextensibility constraint and handling the typically large mass ratio between the segments and the objects they connect. This disclosure introduces an effective approach to solving these problems. The introduced approach simulates the effect of a cable using a new type of distance constraint called 'cable joint' that changes both its attachment points and its rest length dynamically. The introduced approach models a cable connecting a series of objects, e.g., components of a robot, as a sequence of cable joints, reducing the complexity of the simulation from the order of the number of segments in the cable to the number of connected objects.

Simulating a cable driven system representative of a robot

Embodiments of the present invention provide a position-based dynamics approach for simulating objects using a set of points and constraints, applied as equations that restrict the relative motion of bodies. Forces are applied to the points to move them, and the constraints ensure that the points will not move in a way that is inconsistent with rules of the simulation. The present invention improves upon existing PBD approaches by using regularized constraints that directly correspond to well-defined energy potentials, and which can advantageously be solved independent of time step and iteration count.

Position-based dynamics simulation

This disclosure presents a process to generate one or more video frames through guiding the movements of a target object in an environment controlled by physics-based constraints. The target object is guided by the movements of a reference object from a motion capture (MOCAP) video clip. As disturbances, environmental factors, or other physics-based constraints interfere with the target object mimicking the reference object. A tracking agent, along with a corresponding neural network, can be used to compensate and modify the movements of the target object. Should the target object diverge significantly from the reference object, such as falling down, a recovery agent, along with a corresponding neural network, can be used to move the target object back into an approximate alignment with the reference object before resuming the tracking process.

Imitating motion capture clips using a neural network

A cable driving a large system such as cable driven machines, cable cars or tendons in a human or robot is typically modeled as a large number of small segments that are connected via joints. The two main difficulties with this approach are satisfying the inextensibility constraint and handling the typically large mass ratio between the small segments and the larger objects they connect. This disclosure introduces a more effective approach to solving these problems. The introduced approach simulates the effect of a cable instead of the cable itself using a new type of distance constraint called 'cable joint' that changes both its attachment points and its rest length dynamically. The introduced approach models a cable connecting a series of objects as a sequence of cable joints, reducing the complexity of the simulation from the order of the number of segments in the cable to the number of connected objects.

Simulating a cable driven system by simulating the effect of cable portions on objects of the system

Embodiments of the present invention provide a novel method and discretization for animating water waves. The approaches disclosed combine the flexibility of a numerical approach to wave simulation with the stability and visual detail provided by a spectrum-based approach to provide Eulerian methods for simulating large-scale oceans with highly detailed wave features. A graphics processing unit stores a one-dimensional texture referred to as a wave profile buffer that stores pre-computed results at a number of discrete sample points for performing wave height evaluation. The water surface is rendered according to water height values computed using the wave profile, accounting for advection, spatial diffusion, angular diffusion, boundary reflections, and dissipation.

Systems and methods for computer simulation of detailed waves for large-scale water simulation

A simulation engine performs a mass-conserving Eulerian fluid simulation by manipulating the distribution of density between nodes associated with the fluid simulation. The simulation engine traces a velocity field upstream to identify the source of mass that currently resides at a given node. The simulation engine then adjusts (i) the density contributions to that source from adjacent nodes and (ii) the density contributions provided by that source to the given node. In doing so, the simulation engine maintains conservation of mass at a local level between nodes within a given neighborhood. As a result, mass is conserved at a global level. One advantage of the disclosed technique is that a fluid interface associated with the fluid simulation may appear physically realistic, because numerical errors typically caused by violations of conservation of mass may be eliminated.

Mass conserving eulerian fluid simulation

Embodiments of the present invention provide a method for simulating deformable solids undergoing large plastic deformation and topological changes using shape matching. Positional information for particles and orientation information from clusters is used to simulate deformable solids represented by particles. Each visual vertex stores references to particles that influence the vertex, and stores the local position of the particles. A two-step method interpolates orientation from clusters to particles, and uses the orientation and position of particles to skin the visual mesh vertices. This results in a fast method that can reproduce rotation and does not require the visual mesh vertex to be located within a convex hull of particles.

Skinning a cluster based simulation with a visual mesh using interpolated orientation and position

A method and system of representing and simulating an object by representing using with velocity-dependent particles.

Method and system for representing objects with velocity-dependent particles

A strain based dynamic technique, for rendering special effects, includes simulation as a function of a Green-St. Venant strain tensor constraint. The behavior of a soft body may be controlled independent of a mesh structure by assigning different stiffness values to each constraint of the Green-St. Venant strain tensor.

Strain based dynamics for rendering special effects

One embodiment of the present invention sets forth an Eulerian fluid simulation technique which enables real-time simulations of large scale three dimensional fluid volumes that include free surface water. A hybrid grid representation composed of regular cubic cells on top of a layer of tall cells is used to reduce computation time. Water above an arbitrary terrain can be represented without consuming an excessive amount of memory and compute power, while focusing simulation effort on the area near the surface of the water to produce accurate results. Additionally, the grid representation may be optimized for a graphics processor implementation of the fluid solver.

Real-time eulerian water simulation using a restricted tall cell grid

A simulation engine is configured to generate a physical simulation of a chain of particles by implementing a physics-based algorithm. The simulation engine is configured to generate a predicted position for each particle and to then adjust the predicted position of each particle based on a set of constraints associated with the physics-based algorithm. The simulation engine may then generate a predicted velocity for a given particle based on the adjusted, predicted position of that particle and based on the adjusted, predicted position of an adjacent particle.

Technique for simulating the dynamics of hair

One embodiment of the present invention sets forth multigrid generation technique which enables accurate simulations of large scale three dimensional (3D) fluid volumes. A model of the fluid to be simulated is represented using a cell grid. The generated multigrid provides a hierarchy of increasingly coarser representations of the model that are used by a pressure solver. Eulerian simulation techniques require solving a linear system to determine pressure values for each cell within the cell grid. Different levels of the multigrid are then used to compute the pressure values for different regions of the model, maintaining accuracy near the surface of the fluid while simplifying the computations. The accurate pressure values ensure that the simulation produces detailed features of the water movement. Additionally, the multigrid pressure solver may be optimized for execution by a graphics processor.

Multigrid pressure solver for fluid simulation

A method is provided for depicting on a display, an object within a simulated environment having clothing. In this method, the clothing is represented as a series of vertices that include vertices that are attached to the object and vertices that are not attached to the object. The method improves upon position based dynamics algorithm by constraining unattached vertices to be a predefined distance away from attached vertices that are connected thereto to compensate for overstretching in the simulated clothing.

Method of simulating clothing using long range attachments

A system, method, and computer program product are provided for depicting a body of water utilizing a height field and particles. In use, content depicting a body of water is identified. Additionally, a height field is generated for the content. Furthermore, at least a portion of the height field is converted to a plurality of particles based on predetermined criteria.

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Bangkok, Thailand

Nuttapong Chentanez