Schematex
pert·PMI PMBOK 7 + Moder 1983 (AON/PDM)·business, software, education·complexity 2/3

Q3 product launch PERT/CPM network

A seven-task product-launch schedule where the engine computes every Early/Late Start & Finish, total slack, and the critical path (A → C → D → E → G) automatically — the canonical activity-on-node network with the six-field box.

For the project manager

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PERT network — Q3 Product Launch 7 activities, project duration 37 days, critical path A → C → D → E → G. Q3 Product Launch ES 0 DUR 5 EF 5 0 LS 0 SLACK 5 LF Market research A ES 5 DUR 15 EF 20 5 LS 0 SLACK 20 LF Backend API C ES 5 DUR 8 EF 13 12 LS 7 SLACK 20 LF Design mockups B ES 20 DUR 10 EF 30 20 LS 0 SLACK 30 LF Frontend build D ES 13 DUR 7 EF 20 28 LS 15 SLACK 35 LF Marketing collateral F ES 30 DUR 5 EF 35 30 LS 0 SLACK 35 LF QA / testing E ES 35 DUR 2 EF 37 35 LS 0 SLACK 37 LF Launch event G Project duration 37 days · 7 tasks · 8 dependencies · 5 critical Critical path: A → C → D → E → G
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This is what separates Schematex's pert engine from a drag-and-drop "PERT chart maker": you write only the tasks, durations, and dependencies — the schedule is computed.

The six-field box. Each activity renders as the canonical 3×2 PERT/CPM rectangle: Early Start / Duration / Early Finish on top, the task name and id in the middle, and Late Start / Slack / Late Finish on the bottom. Those four schedule fields are never typed by hand — a forward pass walks the network to find ES/EF, a backward pass finds LS/LF, and total slack is LS − ES.

The critical path falls out of the math. Any activity with zero slack is on the critical path and is drawn in red: A → C → D → E → G. Here C (Backend API, 15 days) is the long pole — it dominates B (Design mockups, 8 days) at the D merge, so the schedule pivots on the backend, not the design. Change C to 6 days and the critical path shifts to run through B instead; the render updates because the computation does.

Parallel work, one merge. B and C both start once research finishes, run concurrently, and re-converge at D (Frontend build). F (Marketing collateral) branches off B and carries slack — it can slip several days without moving the launch. The project duration, 37 days, is the maximum Early Finish over the terminal tasks, not simply the last task you declared.

PERT / CPM syntax