Flowcharts and decision diagrams are among the most versatile tools in any engineer's or analyst's toolkit. Whether you are mapping a quality control process, documenting a troubleshooting procedure, or explaining a complex workflow to a client, a well-drawn flowchart communicates in seconds what paragraphs of text struggle to convey.
PfdLabs was originally built for mineral processing and hydrometallurgical flowsheets — but its drag-and-drop editor, shapes and edge routing make it equally powerful for general flowcharts and decision diagrams. Here is how to get started.
The Basic Building Blocks
Every flowchart is built from a small set of standard shapes, each with a specific meaning:
- Pill / Rounded rectangle — Start and End points. The entry and exit of your process.
- Rectangle (Box) — A process step. Something that happens — an action, a calculation, a task.
- Diamond — A decision point. A yes/no or true/false question that branches the flow into two or more paths.
- Text node — Labels, annotations and notes that add context without cluttering the diagram.
A simple decision diagram created in PfdLabs — Start → Process → Decision → Success or Retry
Step-by-Step: Building Your First Flowchart in PfdLabs
1. Start with the endpoints
Always begin by placing your Start and End nodes. In PfdLabs, use the Pill shape from the Add Nodes panel — its rounded form is the universal convention for start and end points. Set the Start node to green and the End node to a contrasting colour such as red or dark green.
2. Add process steps
Use the Box (Rectangle) shape for each process step. Keep labels short and action-oriented — "Collect sample", "Run analysis", "Generate report". If you need more detail, use a sub-label by double-clicking the node and adding a second line of text.
3. Add decision points
Use the Diamond shape for any yes/no decision. The question should be answerable with a clear yes or no — "Data valid?", "Within tolerance?", "Approval received?". Label the outgoing edges with "yes" and "no" so readers can follow the flow at a glance.
4. Connect the nodes
Switch to the Connect tool in the toolbar and click from one node to another to draw an edge. PfdLabs now supports port-based routing — edges connect to the correct side of each node and stay there even when you rearrange the diagram. Choose from Smooth, Angle, Smooth Angle or Straight edge styles depending on your preference.
5. Add arrows and colour
Select any edge and use the Arrow selector in the properties panel to add directional arrows. Use colour to convey meaning — green for success paths, red for error or rejection paths, orange for loops or retries. This makes complex diagrams scannable at a glance.
When to Use a Flowchart vs a Process Flow Diagram
A flowchart maps a sequence of steps and decisions in a process — it focuses on logic and flow. It is ideal for documenting procedures, troubleshooting guides, approval workflows and software logic.
A process flow diagram (PFD) maps the physical flow of materials or energy through equipment in a plant or facility. It uses standardised equipment symbols rather than generic shapes. PfdLabs supports both — use the standard shapes for flowcharts and the Industrial Symbols library for process engineering diagrams.
Tips for Professional-Looking Flowcharts
- Consistent sizing — keep similar nodes the same size throughout the diagram
- Left-to-right or top-to-bottom — pick one direction and stick to it
- Minimal crossing edges — rearrange nodes to avoid edge crossings where possible
- Colour with purpose — use colour to convey meaning, not just decoration
- White space — leave breathing room between nodes; a crowded diagram is hard to read
- Short labels — if a label needs more than five words, consider whether the step can be broken into two
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