Engineering Tools

Idealize Tubes to Beams

Engineering Tools — Idealize Tubes to Beams (00328)

What this tool does

Takes a selection of solid CAD tubes (straight or curved) and converts each one into a meshed CBAR / CBEAM line element idealization with the correct Circular Bar / Tube cross-section property attached. Replaces the older hand-rolled "longest-curve" centerline guess with FEMAP’s native feSolidExtractCenterlines primitive (2020+), which handles both straight and curved tubes robustly and auto-builds the bar property from the CAD wall thickness.

The use case

"I have a CAD assembly with hundreds of structural tube members, and I want a shell-and-line model with line elements for the tubes."

Manually meshing each tube with the right cross-section is a slow click-fest. This tool sweeps through the selection, builds the centerlines, makes the props, meshes them — one click for the whole set.

How to use it

  1. Open from Custom Tools > Meshing > Idealize Tubes to Beams.
  2. Pick the solid tube CAD parts to convert.
  3. Pick the material to use for the new bar properties (defaults sensibly when only one material is in the model).
  4. Choose the per-tube element count (default 10 — enough to capture curvature on bent tubes).
  5. Optionally check Create groups to bundle the new line elements per source tube, and General-purpose beam type to use CBAR vs default CBEAM.
  6. Click OK. Status messages report per-tube progress; the new properties show up in the tree as "Tube OD=… ID=…" labels.

What it does under the hood

  • Centerline extraction — feSolidExtractCenterlines(solidSetID, matID, tubular_only=True) extracts a 3D curve along each tube’s axis and attaches the auto-built Circular Bar property as a mesh attribute on the curve. Robust on straight and curved tubes; doesn’t fall apart on short fat tubes where the older longest-edge-is-the-axis heuristic breaks (because in that case the longest edge is a circumferential circle, not the axis).
  • Sizing — feMeshSizeCurve(set, NumElem, …) seeds each centerline with the user’s element count.
  • Meshing — feMeshCurve2(set, True, 0, True, False, vOrient) with propID=0 so each curve meshes against its own attached property (correct per-tube section automatically).
  • Material handling — if no materials in model: hard abort with a message. If one: silent pick. If multiple: dialog lets the user choose. Avoids the FEMAP-default prompt-per-tube behaviour.

Notes and gotchas

  • This is a defeaturing step — the original solid geometry is preserved alongside the new line elements; you can keep the solids visible for context or hide them via Group/Layer.
  • The created bar property names encode OD and ID so you can spot mistakes quickly if FEMAP picked up the wrong CAD section.
  • Tubes that feSolidExtractCenterlines can’t classify (non-tubular sweeps, joined assemblies) are skipped with a warning — not silently meshed into garbage.
  • Increase the element count from 10 if your tubes have tight curvature; the default works for most aerospace structural members where bend radii are gentle relative to length.

Apache-2.0 licensed. Source available in the Engineering Tools package.