Introduction
The Analysis & Model Utilities commands run the hydraulic analysis and keep the underlying model data clean and consistent. They fall into two groups: the analysis routines that compute results from the network — solving, tracing, and calculating pressures, design factor, and flow efficiency — and the model utilities that adjust and maintain the data those routines depend on, such as customer loads, supply-main assignments, node cleanup, and the undo, redo, and cancel housekeeping commands.
Most analysis routines act on the model’s current state, so the results they report are only as current as the last solve. The utility commands, by contrast, change the data itself — scaling loads, reassigning supply mains, reducing or renumbering nodes — which in turn changes what the next solution produces.
Because of that dependency, solve or regenerate the model after any structural or load change so the results you review reflect the latest network. Enable Allow Undo Of Data/Graphic Changes if you want to be able to reverse a mistake. The articles below group the commands by task.
Articles
- Solving & Tracing the Model
- Use Case: Run the hydraulic analysis and follow flow paths through the network.
- Covers: Full and quick model solutions, tracing connected flow paths (Quick Trace, Trace, and Trace & Update The Data), and regenerating the model data.
- Note: Solve or regenerate the model after structural or load changes so the reported results reflect the current network.
- Calculating Pressures, Design Factor & Efficiency
- Use Case: Compute pressure and pipe-design values for selected features.
- Covers: Pressure drop by the linear and squared methods, pipe design factor, and flow efficiency.
- Note: These routines use engineering formulas — check the model’s default units before reading the calculated values.
- Customer Loads, Supply Mains & Maintenance
- Use Case: Manage customer loads and supply-main assignments and keep customer data consistent.
- Covers: Assigning customer service lines, scaling customer and node loads, reassigning supply mains and renumbering them, purging customers, and updating the pipe customer count.
- Note: Load and supply-main edits change what the solution produces — re-solve the model after making them.
- GDI Utilities: Undo, Redo, Cancel & Housekeeping
- Use Case: Reverse changes and perform general GDI housekeeping and cleanup.
- Covers: Undo and redo of data and graphic changes, canceling the current command, node reduction and renumbering, setting and unsetting valve nodes, removing attached fittings, and user-text utilities.
- Note: Undo and redo require Allow Undo Of Data/Graphic Changes to be enabled before the change is made.
FAQ
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What kinds of tasks live under Analysis & Model Utilities?This subcategory covers running and interpreting the hydraulic analysis itself — solving and tracing the model — along with the calculations built on top of it (pressure drop, design factor, flow efficiency), routine load and supply-main housekeeping, and general-purpose model utilities like undo, redo, and node renumbering.
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When should I use Solve versus Trace?Solve calculates the full hydraulic results for the model — pressures, flows, and related values at every feature. Trace instead follows the gas flow path through the system from a starting point without running a full solution, which is useful for quickly confirming connectivity or flow direction before committing to a full solve.
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Where do I go if I made a change I want to undo, or need to renumber nodes after editing?Both live in GDI Utilities: Undo, Redo, Cancel & Housekeeping. Undo and Redo step backward and forward through your data and graphic changes, while Renumber The Nodes and the other housekeeping commands there handle cleanup tasks like reducing redundant nodes or resetting the numbering sequence after a lot of editing.
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Can I calculate pressure drop or design factor without re-running a full solve?Yes — Calculating Pressures, Design Factor & Efficiency covers these as standalone calculations: Calculate Delta P (Linear), Calculate Delta P (Squared), Calculate The Design Factor, and Calculate The Flow Efficiency can each be run on their own rather than requiring a full model solve.
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How do I bulk-update customer loads or move a batch of customers to a different supply main?Customer Loads, Supply Mains & Maintenance covers both. Multiply Customer Loads and Multiply Node Loads scale load values across a group at once, while Reassign A Customer’s Supply Main and Reassign The Customer’s Supply Main Numbers handle moving customers between supply mains.