533ca91774
Add 18 new constraint classes covering all BaseJointKind types from Types.h: - Point: PointOnLine (2r), PointInPlane (1r) - Orientation: Parallel (2r), Perpendicular (1r), Angle (1r) - Surface: Concentric (4r), Tangent (1r), Planar (3r), LineInPlane (2r) - Kinematic: Ball (3r), Revolute (5r), Cylindrical (4r), Slider (5r), Screw (5r), Universal (4r) - Mechanical: Gear (1r), RackPinion (1r) - Stubs: Cam, Slot, DistanceCylSph New modules: - geometry.py: marker axis extraction, vector ops (dot3, cross3, sub3), geometric primitives (point_plane_distance, point_line_perp_components) - bfgs.py: L-BFGS-B fallback solver via scipy for when Newton fails solver.py changes: - Wire all 20 supported types in _build_constraint() - BFGS fallback after Newton-Raphson in solve() 183 tests passing (up from 82), including: - DOF counting for every joint type - Solve convergence from displaced initial conditions - Multi-body mechanisms (four-bar linkage, slider-crank, revolute chain)
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)