Groups and Drawings

Groups

Groups are colored boxes that wrap related blocks. They help you think in chunks instead of one block at a time.

Make a group

Three ways:

1. Group tool — press G, then click and drag a rectangle on the canvas.
2. From selection — select a few blocks, then press Ctrl+G (or right-click and pick Group selection).
3. From a template — right-click empty canvas space and pick Insert group template to drop in a saved group.

Double-click any group to edit its label and look.

What’s inside

A block counts as inside the group if its center is inside the box. The check is forgiving on purpose so you don’t have to be pixel-perfect.

When you drag a group, every block inside moves with it.

Customize it

Double-click a group to open the editor:

• Label — shows above the group.
• Color — pick from 8 presets.
• Border — solid, dashed, or dotted.

Resize

When a group is selected (or the group tool is on), the four corners become handles. Drag any corner to resize.

Group numbers

After a sim run, each group shows totals for everything inside:

• in — items the group received.
• out — items the group sent.
• drop — items dropped (only shows if there were any).
• util — how busy the group’s blocks were on average.

On the canvas these appear as small text in the top-right of an open group or right below a collapsed one.

In the Overview panel, each group card shows a 4-column grid: Received, Sent, Dropped, Util.

Collapse and expand

You can collapse a group to hide what’s inside:

• Click - next to the group label to collapse.
• Click + on a collapsed group to expand.
• Right-click a group and pick Collapse group or Expand group.

When collapsed:

• The blocks inside are hidden.
• Lines that came in or went out re-route to the collapsed group.
• Lines fully inside the group are hidden.
• The group becomes a small labeled box.

Useful for big systems. Collapse the parts you’re not actively editing.

Save a group as a template

Save a group and reuse it later:

1. Save — right-click a group and pick Save as template. The group, the blocks inside it, and the internal lines all get saved.
2. Insert — right-click empty canvas space and pick Insert group template. A picker shows your saved templates. Click one to drop it onto the canvas with fresh IDs.
3. Delete — in the picker, hover a template and click the trash icon.

Templates live in your browser.

Compare runs (A/B)

When you save a baseline run from the Stress Test panel, the sim saves per-group numbers too. After another run, the sidebar shows the difference for each group:

• In difference (green = more, red = less).
• Drops difference (green = fewer drops, red = more).
• Util difference (green = busier, red = less busy).

Handy for seeing if your change actually helped a specific subsystem.

Overview panel

The Overview panel sorts blocks by group:

• The Groups section lists each group with a colored dot, the label, and how many blocks are in it.
• Click a group row to select it on the canvas.
• Each group card lists the blocks inside.
• Ungrouped blocks show up in their own section below.

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Drawings

Press D for the Draw tool to sketch freehand notes on the canvas. Drawings are just visual — they don’t affect the simulation.