How Quodsi works
Quodsi turns the process diagrams you already draw into simulation models. You draw, you run, you compare.
1. Draw
Start with a process diagram in your diagramming tool: boxes for steps, arrows for flow. Click Convert Diagram to Model and Quodsi reads your shapes. It classifies them by how they connect:
- A shape with arrows going out and none coming in becomes a Generator, where work enters the process.
- A shape with arrows coming in becomes an Activity, a step that takes time. Work queues for it while it is busy.
- An arrow attached at both ends becomes a Connector, the route between steps.
A shape with no connections is skipped. The items that flow through are called entities: patients, orders, calls or parts.
Next you add the numbers, in the Quodsi side panel. Click a shape and its settings appear: arrival rates on the generator, processing times and capacity on each activity. Click empty canvas and you get the settings for the whole model, such as the Run Length.
Your diagram stays a diagram. The model lives in it, and your layout is the layout you see in the results.
2. Run
Click What-if Analysis to open the window where you run and compare. If the model has errors that would stop it running, the button stays disabled until you fix them. The check mark or warning at the top of the Model editor shows the model's state.
Your first run is the Baseline: the model exactly as you drew it, standing in for how the process works today. Quodsi runs it in the cloud, so you don't need to install or configure anything to run a model. Each scenario runs several replications, repeats of the same period with different random draws, so one lucky or unlucky day can't decide the answer. New models use 10.
Then open Results. You get five views:
| View | What it tells you |
|---|---|
| Overview | The headline: Throughput, Time in system, Avg WIP and Total cost, plus what to try next |
| Diagram | Your own diagram with the results shown on it |
| Flow Analytics | Where's the constraint? Every activity ranked by how much it held work back |
| Dashboard | Charts and tables you choose, with + Add a card |
| Animation | The process playing out, for runs recorded with animation |
3. Compare
Now ask your question. A scenario is the model with one or more changes: "What if Check-in had 2 desks?" A study is a set of scenarios run together: "What if Check-in had 2, 3 or 4 desks?"
You build either one in New what-if. It doesn't change your model, so your Baseline stays as it is. In Flow Analytics, the Study button on a row starts a study on that step's constraint for you.
When two or more scenarios have finished, View tradeoff plots them against each other, such as cost along the bottom and throughput up the side. You can see where another desk stops paying for itself. That is usually the conversation your client wants to have.
Where you can use Quodsi
| Tool | What it is for | Availability |
|---|---|---|
| draw.io | Draw, run and compare, with a Quodsi side panel and a Quodsi menu | Available now and free to try |
| Lucidchart | The same work inside Lucidchart, through a Quodsi extension | Early access |
Basic, Intermediate and Advanced views
Quodsi shows you only as much as you need. Choose a view in Settings, under View. New users start in Basic.
| View | What you get |
|---|---|
| Basic | Build, run and cost a complete model: arrivals, activities, routing and levers. |
| Intermediate | Adds resources, states, explicit resource control (seize and release), and calendar time. |
| Advanced | Everything: failures, work schedules, arrival patterns, and full flow control. |
A view only changes what you can see and edit. It never turns behavior off. If a model uses something your view hides, Quodsi tells you with a short notice under the tabs.