circuitcore

PCB analysis toolkit. C++23, Qt6, Eigen, SuiteSparse, optional VTK 9 for 3D field rendering. GPL-3.0.

Four analysis tools share one canonical board model parsed from .kicad_pcb:

• pdnkit -- power integrity
• sikit -- signal integrity
• emikit -- EMI / radiated emissions
• mpkit -- multiphysics (thermal, elasticity, coupled studies)
• studio -- shared shell that hosts all four in tabs

board/         canonical PCB model
sexpr/         s-expression read + emit
field/         shared 3D Field / Grid types
formats/kicad/ .kicad_pcb -> board::Board
netlist/       KiCad netlist reader
ui/            shared Qt canvas + camera
pdnkit/
sikit/
emikit/
mpkit/
studio/

File formats live under formats/. Analysis code only sees board::Board.

---

pdnkit (power integrity)

• Static IR drop. Multi-layer, vias couple planes. CHOLMOD via SuiteSparse.
• Track-based 1D IR drop for pour-less boards.
• IPC-2152 trace-current DRC.
• Cavity-model Z(f) for rectangular planes plus segmentation for arbitrary shapes.
• Decoupling caps in Z(f) with Ruehli mounting inductance, DC-bias derating, vendor-realistic library.
• Decap auto-suggest and leave-one-out sensitivity.
• Target-Z generator from rail spec.
• Time-domain transient solver, per-node C.
• Plane resonance mode-shape visualization.
• Via inductance (Grover / Ruehli partial).
• Djordjevic-Sarkar wideband dielectric.
• Hammerstad-Jensen surface roughness, wired into the cavity model.
• VRM output impedance overlay on Z(f).
• IR + thermal coupling (temperature-corrected sigma, fixed-point loop).
• Model order reduction via Schur complement, reduced SPICE export.
• SPICE netlist export, Touchstone .s1p writer.
• HTML signoff report (board summary, IR, DRC, Z(f), verdict).

CLI: --analyze, --zf, --touchstone, --transient, --drc, --probe-r, --target-z, --list-nets, --list-layers, --version.

sikit (signal integrity)

• Trace impedance: Wadell closed-form plus in-house FDM solver.
• Cross-section / stackup model.
• S-parameter read + write (Touchstone .s2p), CSV.
• Vector fitting, rational SPICE export.
• Eye diagrams: time-domain Eye, StatEye, EyeMetrics, EyeMask, Bathtub.
• IBIS parser, IBIS-AMI support.
• Diff pair synthesis and analysis.
• Crosstalk, skew, bus-skew.
• Return-path analysis.
• Via model.
• FDTD3D solver with PEC rasterizer and lumped port for S-param extraction.
• Connector model, channel synthesis + response.
• Built-in compliance specs (list-specs), de-embedding, comparison report.
• Djordjevic-Sarkar + HJ roughness.

CLI: impedance, touchstone, spice, compliance, deembed, compare, skew, bus-skew, return-path, report, derive-topology, fdtd info, list-specs, list-nets.

emikit (EMI)

• Loop-emission estimator (di/dt over loop area).
• Cable common-mode model.
• Calibration against TI ADS8686S chamber data (see emikit/VALIDATION.md).
• Mask check against built-in EMC specs.

CLI: check, list-masks.

mpkit (multiphysics)

• Voxel rasteriser turns a parsed board into a 3D material grid.
• Steady-state 3D heat solver, finite-volume on the voxel grid, harmonic-mean conductivity across material interfaces, sparse Cholesky.
• Transient 3D heat solver, implicit backward Euler.
• Linear elasticity solver, Q1 hex FEM, body force + thermal-strain source.
• Joule coupling: pdnkit IR solution -> volumetric heat source.
• Thermoelectric post-processor: Seebeck, Peltier, Thomson primitives; Material gains Seebeck coefficients for the standard thermocouple + TE-cooler metals (chromel, alumel, constantan, bismuth, ...).
• Study orchestrator: a Study tree of physics nodes + couplings is walked end-to-end. Multi-parameter full-factorial sweeps. Persisted as .mpstudy sexpr plus binary .mpfield sidecars.
• All solvers verified against analytical solutions (1-D linear / parabolic / series-slab conduction; closed-form first-mode decay; uniaxial compression; hydrostatic thermal constraint; Type-K thermocouple sensitivity).

studio

One window, five tabs (Board / SI / PI / EMI / Mp), single shared board. Drop a .kicad_pcb and click between PI / SI / EMI / Mp without re-loading.

The Mp tab uses VTK 9 via QVTKOpenGLNativeWidget for the 3D viewer (orbit / pan / zoom camera, XYZ gizmo, axis-aligned slice plane, colormap legend, four built-in colormaps). VTK is built from source via CMake FetchContent against Qt6, since the Debian apt package ships against Qt5 and silently mismatches. First configure on a fresh machine takes ~15-20 min; subsequent builds reuse the cached build tree.

---

Build (Ubuntu 24.04)

sudo apt install -y qt6-base-dev qt6-base-dev-tools \
    libqt6opengl6-dev libqt6openglwidgets6 \
    libeigen3-dev libsuitesparse-dev libcgal-dev \
    libspdlog-dev libcli11-dev libboost-dev \
    libopenmpi-dev \
    ninja-build cmake clang-18 catch2

CC=clang-18 CXX=clang++-18 cmake -B build -G Ninja
cmake --build build
ctest --test-dir build

To skip the VTK build (the Mp tab loses the 3D viewer; everything else is unchanged):

cmake -B build -G Ninja -DCIRCUITCORE_BUILD_MPKIT_WIDGETS=OFF

Binaries land in build/pdnkit/pdnkit, build/sikit/sikit, build/emikit/emikit, build/studio/circuitcore_studio.

---

Validation

• 700+ unit + integration tests across all kits.
• pdnkit/tests/ -- Ohms-law fixture, Wadell verification, full IR + cavity + transient + sensitivity pipeline test.
• mpkit/tests/ -- analytical conduction, parabolic with source, series copper/FR-4 slab, first-cosine decay, uniaxial compression, hydrostatic thermal constraint, Type-K thermocouple sensitivity.
• emikit/VALIDATION.md -- TI ADS8686S chamber-data correlation.
• Sikit FDTD validated against analytic stripline + planar-waveguide cases.

Using circuitcore as a dependency

Consumable via add_subdirectory or FetchContent; apps, tests and the VTK-backed mpkit widgets switch OFF automatically when circuitcore is not the top-level project.

include(FetchContent)
FetchContent_Declare(circuitcore
    GIT_REPOSITORY https://github.com/UnsignedChad/circuitcore.git
    GIT_TAG        v0.1.0-alpha.4)
FetchContent_MakeAvailable(circuitcore)

target_link_libraries(myplugin PRIVATE pdnkit::widgets circuitcore::kicad)

Library targets: circuitcore::{board,sexpr,netlist,kicad,field,ui}, pdnkit::{pi,widgets}, sikit::{si,widgets}, emikit::emi, mpkit::{mp,widgets}. See tests/consumer/ for a minimal consumer.

Contributing

See CONTRIBUTING.md. CI runs gcc-13 on Ubuntu 24.04. CODEOWNERS gates shared modules. Auto-merge on green.