Orthogonal wiring
Snapping, branching onto existing wires, junctions, named nets, segment editing, and undo for every gesture.
Open-source multidomain simulation
Draw the system.
Simulate it.
Gradara is a graphical workbench for electrical, mechanical, thermal, and control models. Wire a diagram, set parameters, and run it with the OpenModelica solver on your own computer.
Free · Windows, macOS, Linux · Apache-2.0 · Early release
Multidomain
Real physics on every port.
Physical connections follow conservation laws, so a circuit behaves like a circuit and a shaft carries torque. Signals and physics meet through explicit sensors and actuators.
Signal & control
Sources, math, transfer functions, discrete and sampled blocks, PI and PID, transforms.
causal · scalarElectrical
Sources, passives, ideal switches, bridges, transformers, inverters, and motors.
v · iRotational mechanics
Inertias, loads, damping, and speed and torque sensors coupled to machines.
φ · τThermal
Heat capacity, conduction, and losses for lumped thermal and cooling models.
T · Q̇The workbench
Built for engineers
who draw first.
Direct manipulation stays fast, and the numerical work goes to a proven Modelica compiler and solver. Your models are plain files on your computer.
OpenModelica inside
Models compile to Modelica and run with OpenModelica 1.27 and the Modelica Standard Library 4.1.0, including events and stiff systems.
Results inspector
Plot any logged net or output, zoom into switching ripple, keep event pairs, and download the full CSV.
Worked examples
DC motor speed control, field-oriented control, a synchronous buck, a 480 VAC flyback, and data center cooling.
Inspect and export
Read and edit block equations, export Modelica source, and generate compile-checked C11 for a controller block.
Local and private
Everything runs on your computer. No account needed to model or simulate, and no analytics or tracking.
Optional AI
Describe the missing part.
Get a checked block.
When the library does not have what you need, describe it. Gradara writes the equations, checks them with the compiler, and places a block you can inspect and edit. It can also build a complete first model from a description.
Describe
Choose signal, electrical, mechanical, thermal, or multidomain, and say what it should do.
Generate
The AI returns a structured definition with real ports and parameters, never free-form code.
Check
Schema validation and the OpenModelica compiler run before anything reaches your diagram. One automatic repair if needed.
Own it
The block is saved in your model and your local library. Reuse and simulate it without calling AI again.
› A thermal model of a MOSFET on a heatsink with junction, case, and ambient nodes
generating definition · 3 heat ports · 4 parameters
compiler check passed · placed as MOSFET thermal
generating definition · 3 heat ports · 4 parameters
compiler check passed · placed as MOSFET thermal
Illustrative request. Results depend on the description and the chosen block type.
Pricing
The workbench is free.
AI is pay as you go.
Buy prepaid credits inside the app when you need them, or use your own AI account. No subscription and no card on file.
Gradara
Free
The complete workbench, forever.
- Modeling, simulation, and results
- All examples and export formats
- Your own OpenAI or Anthropic key, billed by them
- Open source under Apache-2.0
Gradara AI · Starter
$10 100 credits
Sign in and go. No keys or setup.
- 20 free credits when you sign up
- Repair attempts included
- Not charged if the service fails
- Credits never expire while your account is active
Gradara AI · Pro
$50 550 credits
For regular use across projects.
- 10% more credits per dollar
- Same checks and privacy
- Receipts by email from Stripe
- Buy from Settings in the app
2credits per generated block
20credits per complete model build
2credits per C controller export
Privacy
Your models stay
on your computer.
Gradara is local first. Nothing leaves your computer unless you ask for an AI feature. Read the privacy notice.
No content retention
Gradara AI processes requests in memory. Prompts, models, equations, and responses are never stored or logged.
Minimal records
Only your email, credit balance, purchases, and request counts, with usage records deleted after about 13 months.
Keys in your keychain
Your own API keys and your sign-in live in the operating system keychain and go only to their provider.
Delete any time
Delete your Gradara AI account from Settings. Your local models are never affected.
Download
Install in minutes.
On first launch, Gradara walks you through a one-time simulation engine setup for your platform.
Windows
Windows 10 or 11, 64-bit. Gradara guides you to install OpenModelica, then adds its component library.
Installer · x64macOS
Apple silicon or Intel. Simulations run in a lightweight container with OrbStack, Docker Desktop, or Colima.
Disk image · .dmgLinux
64-bit Linux. Uses OpenModelica's packages, or Docker if you prefer containers.
AppImage · Debian and UbuntuPrefer to build it yourself? Clone the repository and follow the setup guide. Release notes are on GitHub Releases.
FAQ
Questions.
Is Gradara really free?
Yes. The app is open source under Apache-2.0 and every modeling and simulation feature is free. Only the optional hosted AI uses paid credits, and you can use your own AI account instead.
Do I need Docker?
Not on Windows or Linux, where Gradara uses an installed OpenModelica. On macOS, OpenModelica does not publish native builds, so Gradara runs it in a lightweight container through OrbStack, Docker Desktop, or Colima.
Can it open Simulink models?
No. Gradara is an independent tool with its own model format and exports standard Modelica source. MATLAB and Simulink files are not supported.
Does my model leave my computer?
Only when you use an AI feature, and only the context that request needs. Gradara AI never stores it. Simulation always runs locally.
Can I trust AI-generated blocks?
Every block passes schema checks and the OpenModelica compiler before it appears, and its equations are visible and editable. Compiling is not the same as being physically correct, so review blocks the way you would review any model.
Who makes Gradara?
Gradara is developed by Virtu Services LLC, with contributions from the open-source community.
Start with an example.
Simulate in minutes.
Open the DC motor or the buck converter, press Run, and explore the results.