forbes-0023 9dad25e947 feat(solver): assembly integration — diagnose, drag protocol, system extraction (phase 5)
- Extract _build_system() from solve() to enable reuse by diagnose()
- Add diagnose(ctx) method: runs find_overconstrained() unconditionally
- Add interactive drag protocol: pre_drag(), drag_step(), post_drag()
- Add _run_diagnostics() and _extract_placements() helpers
- Log warning when joint limits are present (not yet enforced)
- KindredSolver now implements all IKCSolver methods needed for
  full Assembly workbench integration
2026-02-20 23:32:51 -06:00
2023-10-17 09:56:26 -05:00

Kindred Solver

Assembly constraint solver addon for Kindred Create. Implements the IKCSolver interface via kcsolve.register_solver().

Components

Kindred Solver (Phase 1)

Expression-based Newton-Raphson constraint solver. Pure Python, registered as a Create addon.

  • Expression DAG with eval, symbolic differentiation, simplification: kindred_solver/expr.py
  • Parameter table with fixed/free tracking: kindred_solver/params.py
  • Quaternion rotation as polynomial Expr trees: kindred_solver/quat.py
  • RigidBody entity (7 params: position + unit quaternion): kindred_solver/entities.py
  • Constraint residual generators (Coincident, DistancePointPoint, Fixed): kindred_solver/constraints.py
  • Newton-Raphson solver with symbolic Jacobian: kindred_solver/newton.py
  • Pre-solve passes (substitution, single-equation): kindred_solver/prepass.py
  • DOF counting via Jacobian rank: kindred_solver/dof.py
  • KCSolve IKCSolver bridge: kindred_solver/solver.py

GNN (future phases)

Graph neural network constraint prediction layer. OndselSolver C++ engine and ML training infrastructure. Moved to GNN/ — will be integrated in later phases.

Create Addon Integration

This repo is a git submodule at mods/solver/ in the Create repository. The addon loader discovers package.xml and executes Init.py, which registers the solver:

import kcsolve
from kindred_solver import KindredSolver
kcsolve.register_solver("kindred", KindredSolver)

Testing

python3 -m venv .venv && . .venv/bin/activate
pip install pytest numpy
PYTHONPATH=. pytest tests/ -v

Repository Structure

├── package.xml            # Create addon manifest
├── Init.py                # Solver registration entry point
├── kindred_solver/        # Phase 1: expression-based Newton solver
│   ├── expr.py            # Expression DAG
│   ├── params.py          # Parameter table
│   ├── quat.py            # Quaternion math as Expr trees
│   ├── entities.py        # RigidBody entity
│   ├── constraints.py     # Constraint residual generators
│   ├── newton.py          # Newton-Raphson solver
│   ├── prepass.py         # Pre-solve passes
│   ├── dof.py             # DOF counting
│   └── solver.py          # IKCSolver bridge
├── tests/                 # Unit tests (82 tests)
└── GNN/                   # GNN solver layer (future phases)

License

LGPL-2.1-or-later (see LICENSE)

Description
An assembly solving stack for Kindred Create based on a trained GNN layer between placement actions in the UI and actual constraints applied.
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