NX Routing: Minimum Bend Radius Checking in Practice

Minimum bend radius is one of the most commonly discussed routing "design rule" checks in practitioner forums, because violating it produces parts (tubes, cables, hoses) that cannot actually be manufactured or installed as drawn. This note aggregates practitioner-level detail on how the check is actually run day to day.

Where the check lives

NX's routing design-rule set includes checks for minimum bend radius, minimum length, connection compatibility, flow direction, and other route characteristics — described in official material as an "expandable design rule set," meaning shops can add custom rules on top of the standard ones.

In practice, users run the check two ways:

1. Analysis → Minimum Radius — an interactive tool for checking bend radius by iteratively adjusting control points and re-checking, useful while actively editing a route.
2. Analysis → Check Mate → Run Tests (or enabling automatic error reporting in preferences) — a batch-style design rule check that flags all minimum-bend-radius spline violations across the route(s) in one pass, rather than checking point by point.

(Source: NX Unigraphics Tutorial: Routing Systems)

What the violation actually tells you

When a spline violates the minimum bend radius design rule, NX highlights the specific violation location on the curve — i.e., it points directly at the sharp corner/tight bend rather than just flagging "this route has a problem somewhere." This is what makes the batch Check Mate pass practical on long, complex routes: you don't have to visually hunt for the offending segment.

Related tool: Measure Distance for path length

Alongside bend radius checking, Analysis → Measure Distance is the standard tool practitioners use to calculate path lengths along a curve or routing path — useful for verifying stock-length assumptions or cross-checking against a bill-of-material length before committing to a design.

Related tool: Smart Router "Quick Path"

Worth noting alongside bend-radius checking: NX's Quick Path (Insert → Routing Path → Quick Path) automatically generates a collision-free path between two specified locations, optionally through intermediate waypoints, producing a path built from lines and arcs that already maintains clearance from obstacles. Practitioners use this as a fast first-pass route generator, then run the bend-radius/design-rule checks against the result rather than hand-drawing every path from scratch. This two-step pattern (auto-generate path → verify with design rules) shows up repeatedly across the informal tutorial content reviewed for this note.

Practical takeaway

The consistent practitioner pattern across sources is: don't treat bend-radius checking as a one-time end-of-design gate. Use the interactive Minimum Radius tool while actively laying out a tight or complex section, then run a full Check Mate design-rule pass before release to catch anything missed interactively — especially on longer assemblies where a purely interactive, point-by-point check is impractical.

Source: NX Unigraphics Tutorial: Routing Systems