SIMULATION · SYSTEMS BASE EDITION AND MODULES · WINDOWS AND FUSION OSFusion SIM is Fusion's simulation product. Its Systems base edition models electrical, mechanical, thermal and fluid networks with control blocks in one schematic, and modules add each field of engineering: Electronics, Structural, Thermal and Dynamics are in development now. It is built in C++ for Windows and Fusion OS, and goes with Fusion CAD.
Fusion SIM's development build: a DC motor spinning up a flywheel, electrical and mechanical parts in one schematic.
One schematic for every physical domain.
The Systems base edition solves every domain with the same nodal analysis. Nets take the domain of the parts on them and are drawn in its colour, and parts such as a DC motor or a sensor join one domain to another.
Electrical
Resistors, capacitors, inductors, transformers, switches, independent, controlled and behavioral sources, in volts and amperes.
Translational mechanics
Masses, springs, dampers and force and velocity sources, in metres per second and newtons.
Rotational mechanics
Inertias, torsional springs, rotational dampers, torque and speed sources, and the shaft of a DC motor.
Thermal
Thermal resistances and masses, heat sources and fixed temperatures, in degrees Celsius and watts.
Fluid
Pipes, tanks, pumps and pressure sources, in pascals and cubic metres per second.
Signals and control
Gains, sums, integrators, functions, sensors and controlled sources that close control loops around the physical parts.
Examples checked against exact answers.
Fusion SIM comes with worked examples, and each one is tested against its closed-form answer. Every picture on this page is a screenshot of Fusion SIM's development build.
A 1 N step on a mass, spring and damper rings at 10 rad/s with a damping ratio of 0.1.10 W through a heatsink to 25 °C air settles at 50 °C at the junction and 45 °C at the heatsink.A dual op-amp placed from a part library: two amplifier units and a supply unit, simulated as one part. Electronics module.A 2N3904 common-emitter amplifier, with its gain within 1 % of small-signal theory. Electronics module.An inverting op-amp amplifier's frequency response, within 1 % of theory up to 2 MHz. Electronics module.A buck converter at 100 kHz: its output within 30 mV of half the input less half a diode drop. Electronics module.
Field modules on Fusion CAD parts.
Structural, Thermal and Dynamics mesh a Fusion CAD part straight from its geometry, refer to the part instead of copying it, and show their results on the part in 3D, drawn by Fusion 3D Engine.
Structural: 1 kN sideways on a Fusion CAD bracket, von Mises stress on the deformed part and the reaction at its base.Thermal: 10 W into the upright, the base held at 40 °C; the heat each load puts in balances to zero.Thermal: two bodies joined by a thermal pad, cooled by convection and radiation, solved by Newton's method.Dynamics: the bracket's first ten natural frequencies and mode shapes, with the share of the mass each moves.
A workbench that answers as you change it.
The schematic and its results sit side by side. Probe the schematic to plot what you need, then change a value and watch the results follow.
Schematic capture
Place parts from part libraries, wire them and name nets with labels; organise large circuits in sheets with sheet blocks and buses. Wires follow when parts move, unconnected pins are marked, and every edit can be undone.
Probe the schematic
Click a net to plot it, a part for its current, or Alt+click for its power. Operating-point values appear right on the schematic.
Waveform viewer
Plots grouped by unit, zoom and pan, two cursors, Bode plots of frequency responses and spectra of transients.
Measurements
Minimum, maximum, peak-to-peak, average and RMS between the cursors, or the −3 dB points of a frequency response.
Tuners
Drag a slider on a part's value and the simulation runs again in the background, with the plots and measurements following.
Analyses and sweeps
Operating point, DC sweep, AC and transient analyses, with sweeps of parameters, part values and temperature overlaid run by run.
Add a module for each field of engineering.
Fusion SIM is the Systems base edition plus modules that you add as your work needs them. Every module shares the same workbench and the same files.
Systems
BASE EDITIONMulti-domain networks of electrical, mechanical, thermal and fluid parts with control blocks, the schematic editor, the waveform viewer and the analyses.
Electronics
IN DEVELOPMENTSPICE netlists, subcircuits and models; diodes, Zener diodes and LEDs; bipolar transistors and MOSFETs; op-amps, including manufacturers' models; library parts of several units.
Structural
IN DEVELOPMENTLinear static stress in solids: displacement, von Mises stress, safety factor and reactions on meshes of Fusion CAD parts, and thermal stress at a uniform temperature or a Thermal study's.
Thermal
IN DEVELOPMENTSteady and transient heat conduction with convection and radiation, properties that change with temperature, loads that change in time, and bodies joined by contact conductances.
Dynamics
IN DEVELOPMENTNatural frequencies and mode shapes with effective masses, harmonic response with damping, and transient response to loads that change in time.
Motion
PLANNEDMechanisms from Fusion CAD assemblies, driven through their joints, motors and contacts.
Fluids
PLANNEDInternal and external flow, with heat transfer between fluids and solids.
Electromagnetics
PLANNEDLow-frequency magnetic fields in motors, transformers, actuators and inductors.
And later
ROADMAPEmbedded systems, RF and signal integrity, acoustics, advanced structural analysis, design optimization and batteries.
Answers you can check.
The solvers are written in C++ and tested against closed-form solutions, so you can see how close each answer is.
Semiconductors
Diode operating points within a nanovolt of the exact solution at tight tolerances, and bipolar transistor currents within a picoampere of their model equations.
Transients
An RC step within 16 µV of the exact exponential on 5 V, and a switch's closing time located within a nanosecond.
Structures
A cantilever's tip deflection within 2 % of beam theory, a thick pipe's expansion under pressure within 0.5 % of Lamé's solution, and a bar held at both ends carrying exactly −EαΔT when heated.
Heat
A bar radiating from its end within 0.00000004 K of the exact temperature, and two bars joined by a contact conductance agreeing to eleven digits, though their meshes do not match.
Vibration
A slender cantilever's first bending frequency within 0.4 % of Euler–Bernoulli theory, and a damped resonance's peak, width and phase as a single oscillator gives them.
Checked on both systems
These closed-form checks run as tests on Windows and on Fusion OS, so an answer that drifts fails them.
Open files and exchange.
Schematics are saved as .fschematic files and projects as .fsim files, both readable JSON. Fusion SIM also reads and writes the formats engineers already use.
.fschematic schematics
The parts, wires, labels, sheets and analyses of a schematic, with the netlist generated from it whenever it runs. Fusion EDA reads the same files through the library both products share, so a circuit tried in Fusion SIM can start a board design.
.fsim projects
A project holds a study, with its geometry, material, fixtures and loads, or a circuit with its plotted signals and tuners. Projects refer to their Fusion CAD part or schematic instead of copying it, so they follow the design as it changes.
SPICE, CSV and VTK
Open SPICE netlists with their models and subcircuits, export circuits to ngspice, plots to CSV and PNG, and structural, thermal and dynamics results to VTK for ParaView.
Part of the Fusion platform.
Fusion CAD
Fusion SIM goes with Fusion CAD. Structural, Thermal and Dynamics mesh Fusion CAD parts straight from their Open CASCADE geometry, and export them again when the part changes.fusioncad.cloud →
Fusion 3D Engine
Fusion's core 3D engine draws Fusion SIM's 3D results: stress on the deformed part, temperatures and mode shapes; flow comes with the Fluids module.fusion3d.cloud →
Fusion OS
Fusion SIM is built in C++ to run natively on Fusion OS as well as on Windows.Fusion OS →
