Patents

Read this first

This document is a factual inventory, not a legal opinion, and it cannot tell you whether any implementation infringes anything. Infringement is a claim-by-claim legal determination that depends on claim construction, the doctrine of equivalents, validity, prosecution history, and jurisdiction — none of which is assessed here and none of which a non-lawyer should assess. Nothing below is legal advice.

What it is for: to put the question on the record, to make a patent-counsel engagement cheap and well-scoped by doing the fact-gathering in advance, and to let engineering decisions be made with the landscape visible instead of invisible.

1. Why this file exists

A bibliography grades novelty exclusively against publications, and a license audit catalogs source licenses — References does both. Neither touches patents, and patents are a different instrument:

A paper documents. It creates prior art and a citation obligation.
A source license governs copying that code. References §4 catalogs the licenses of the reference implementations; the strict discipline is “methods only, never code” for GPL and unlicensed repositories.
A patent grants the right to exclude others from practicing the claimed invention regardless of whether you ever saw their paper or their code. Independent invention is not a defense. Reading the paper instead of the source does not help. This is the axis a bibliography never examines.

That gap matters more for a proprietary implementation intended to ship in a commercial product than for an academic one.

2. How this inventory was built, and what is missing from it

Method. Google Patents full-text and CPC-scoped queries (G06T13/60 natural-phenomena animation, G06T13, plus assignee sweeps), Crossref/Justia/USPTO cross-checks, and direct retrieval of claim text where the host allowed it. Every patent number, assignee, and date below was read off the patent record, not off a search summary.

Retrieving claim text. Google Patents rate-limits, and the USPTO image-ppubs grant PDFs have no text layer — but they can be read as page images, which is how the claims of US11966999B2, US11373353B1, and US11145099B2 were retrieved. pat2pdf.org is dead — it depended on USPTO’s retired legacy image server.

This sweep is incomplete, and the gaps are specific. Before any counsel engagement, expect to close:

Gap	Why it matters
Continuations and pending applications not traced	A granted patent’s continuity chain may contain live applications with different claims. The five Disney documents are not one family: A, D, and G are separate; B and E are related by a continuation-in-part but have separate public family records. Each chain needs its own search.
Non-US jurisdictions only partly traced	A first family pass found US-only public country tables for A, B, D, and E, while F has US, PCT, and CN members. This is not an official global-family search. EP/CN/JP and national-phase records still need counsel review for every chain.
Chinese assignees only spot-read	Two directly relevant grants were located and read: Tencent’s active `CN112862942B`, claiming a position-sorted, per-particle-thread MPM path (row I), and East China Normal University’s `CN116092613B`, claiming phase-transition elastoviscoplastic MPM (row K). That closes the most obvious Chinese blind spots, not the jurisdiction. Other Chinese MPM patents and Chinese-language prosecution records remain unswept.
Not every common MPM mechanism is swept	The sweep was organized around transfer schemes and constitutive models. Position-based MPM (row J), CPIC-style cutting, multi-field contact, active-region worklists, and surface reconstruction were not searched as claim concepts.
Inventor sweeps incomplete	Stomakhin and Chenfanfu Jiang were rate-limited and did not run. The Teran query failed to surface known `US11145099B2`, so inventor-search counts and all “nothing located” results are preliminary leads, not evidence of absence.
Legal status and term not independently verified	Public aggregator fields supply the reported adjusted dates and flag H1’s fee-related lapse, but maintenance, terminal disclaimers, revival, continuity, and assignment must be checked in official USPTO records before a decision.

3. The inventory

Sorted by how directly the claimed subject matter touches a typical real-time MLS-MPM implementation.

#	Patent	Title	Assignee	Priority	Reported term/status	What it claims
A	US10503845B2	Particle-in-cell methods preserving shearing and rotation	Disney Enterprises	2015-12-28	Active; adjusted expiration reported 2037-09-01	APIC itself (Jiang et al. 2015): particle→grid and grid→particle transfers carrying angular-momentum information, stored in a per-particle matrix, inside an MPM loop. The independent claims recite no rendering step.
B	US10019827B2	Material point method for simulation of granular materials	Disney Enterprises	2013-12-31	Active; adjusted expiration reported 2036-07-31	Claim 1 recites the Stomakhin 2013 snow energy density exactly — fixed-corotated shear, the $(\lambda/2)(J_E - 1)^{2}$ volumetric term, exponential hardening $\mu_0 e^{\xi(1-J_P)}$ , $\lambda_0 e^{\xi(1-J_P)}$ — in a rasterize, update, render loop for a granular material.
C	US11966999B2	Real-time simulation using material point method on GPUs	Tencent America LLC (Fei, Gao)	filed 2022-03-04	Active; adjusted expiration reported 2042-09-24	Every independent claim requires multiple GPUs and a particle↔︎grid-block mapping rebuilt less often than it is used (the “free zone”). Dependent claims add native atomics and warps whose particles share a grid block.
D	US10733336B2	Adaptive material point method	Disney Enterprises	2015-01-16	Active; adjusted expiration reported 2037-01-06	The patent counterpart of adaptive GIMP (Gao et al. 2017). Claim 1 requires all of a dynamically updated non-uniform grid, particle merging away from the surface, and two different transfer functions tied to the grid’s compatibility constraint.
E	US10210287B2	Augmented MPM for simulating phase changes and varied materials	Disney Enterprises	2013-12-31	Active; adjusted expiration reported 2035-08-22	Stomakhin 2014: a deviatoric/dilational split of the constitutive model plus a grid pressure projection correcting intermediate grid velocities, for phase transitions.
F	US11373353B1	Heuristic scheme in material point method for simulating material	Tencent America LLC (Fei, Gao, Guo, Wu)	filed 2021-02-26	Active; anticipated expiration reported 2041-02-26; CN member pending	ASFLIP (Fei et al. 2021): a G2P with the velocity blend $\alpha\left(\mathbf{v}_p - \sum_i w_{ip} \mathbf{v}_i\right)$ plus a per-particle $\beta_p$ position-adjustment term; a further claim recites the heuristic that sets $\beta_p$ .
G	US11062060B2	Guided simulation with generalized collision objects	Disney Enterprises	2016-09-09	Status/term require official verification	Collision-object handling; claim 1 is narrow and specific — a 3D shape dividing material into inner and outer portions around an advancing solid, with surfaces acting as source, sink, and impenetrable collider.
H1	US11145099B2 (was `US20200082589A1`)	Computerized rendering of objects having anisotropic elastoplasticity for codimensional frictional contact	UC Regents (Teran, Jiang, Gast)	2017-05-17	Reported expired — fee related after its first maintenance window; exact effective date and possible revival not assessed	Codimensional MPM — cloth, knit, hair (SIGGRAPH 2017). Claim 1 is limited to a codimensional object; claim 13 to a mesh representation with orthogonal-component frictional contact.
H2	US20200302672A1 / `WO2019074856A1`	Computerized rendering of animated objects using polynomial particle-in-cell	UC Regents (Teran, Jiang, Gast, Fu, Guo)	2017-10-09	US application reported abandoned 2021-10-23; PCT reported ceased	PolyPIC transfers (Fu et al. 2017).
I	CN112862942B	Physical special-effect simulation method, device, electronic equipment and storage medium	Tencent Technology (Shenzhen)	2021-02-08	Active; anticipated expiration reported 2041-02-08	Position-sorted, per-particle-thread MPM (machine translation): sort particles by position, derive each particle’s processing thread and particle↔︎cell mapping from the sort, interpolate attributes to the cell’s grid nodes, compute the motion update from them.
J	No public filing located in the preliminary search	Position-Based MPM (PB-MPM)	EA SEED paper/code origin	published 2024	Unresolved; a search null is not clearance	The iterative compliant-constraint PB-MPM formulation. EA’s own page calls it “novel”, which is a reason to search carefully, not evidence that a patent exists.
K	CN116092613B	Simulation method for phase transition of elastic-viscoplastic materials based on MPM	East China Normal University	2023-02-13	Granted 2025-12-30; reported active. A bounded public-family search surfaced no US, PCT, or other national member	Machine-translated claim 1 is a conjunction: an MPM/APIC simulation; a unified phase-transition elastoviscoplastic model combining Von Mises with Drucker-Prager or Cam-Clay behavior; Allen–Cahn / Cahn–Hilliard phase-field discretization; and phase-field-driven interpolation of friction, cohesion, hardening, and viscosity. A standalone J2 return with linear hardening carries none of the phase-transition, hybrid-surface, or phase-dependent-interpolation elements — a distinction for counsel to evaluate, not a conclusion.
L	US11530581B2	Weighted material point method for managing fluid flow in pipes	(oil & gas)	—	Not analyzed	Different field; cataloged for completeness.
M	US8947430B1	System and method for rendering a particle-based fluid surface	NVIDIA (van der Laan, Sainz, Green)	filed 2010-02-26	Granted 2015-02-03; reported active, expiration reported 2032-09-15	The rendering-side entry, for any particle method. Claim 1 is a conjunction: a depth image of the particles each rendered as a screen-oriented quad; smoothing that depth image; surface positions and normals from the smoothed depth; shading from them; and a per-pixel fluid thickness accumulated with a specific spherical-cap kernel. Curvature flow is the specification’s example smoother, not a claim limitation. A 3D-field raymarch shares none of these elements; a screen-space design shares most of them.

The concentration is the story. Five of the seven most relevant patents are Disney Enterprises, and they are the patent counterparts of exactly the papers every MPM bibliography is built on — Stomakhin 2013/2014, APIC 2015, Gao 2017 adaptive GIMP. References cites those papers as foundations. Their patent shadows are rarely noticed.

4. Read, copy, practice: three separate questions

The techniques the field treats as free, well-understood building blocks have a mixed patent record: active issued claims were located for APIC, the Stomakhin snow model, and ASFLIP; a published but abandoned US application was located for PolyPIC; a separate active Chinese grant reaches a position-sorted MPM execution shape; and a second Chinese grant reads on phase-transition elastoviscoplastic MPM as a conjunction of elements. A bibliography and a license audit both miss this axis because both are designed to answer different questions.

The rule that follows from it:

A paper being freely readable, and a reference implementation being permissively licensed, are two independent facts — and neither one is evidence about patents. A bibliography answers “can I read it,” a license audit answers “can I copy that code,” and only a patent inventory asks “may I practice the method.” Adding a technique needs all three answered.