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The Design step

The Design step holds everything about the shaft as a whole. The three groups below (general properties, section lengths, and pull-wire settings) all live on this one step, laid out in two columns.

General Properties​

  • Load Config from File: Loads a previously saved catheter design from a configuration file. This bypasses the setup wizard and immediately jumps to the Review and Build step. Also accessible via File > Load Config.
  • Catheter name: Assign a unique, descriptive name for your catheter design. This name will be automatically used in generated reports and assigned to exported images and data logs.
  • Design mode: Selects how the catheter layers will be constructed for each section.
    • Fixed ID: Keeps the Inner Diameter (ID) of the catheter (mandrel) constant and adjusts the Outer Diameter (OD) based on the configured layer stackup. Set the Inner (mandrel) diameter in the input field below.
    • Fixed OD: Keeps the Outer Diameter (OD) of the catheter constant and adjusts the Inner Diameter (ID) based on the configured layer stackup. Set the Outer diameter in the input field below.
    • Fixed OD and Fixed ID: Keeps both the Outer Diameter (OD) and the Inner Diameter (ID) of the catheter constant. In this mode, the user selects one layer in the stack, the jacket by default, to adjust its thickness to meet the target ID and OD. Set the ID and OD in the input fields below.
    • Multi-Lumen Core: Builds the catheter inside-out on a shaped multi-lumen extruded core (double-D, satellites, crescent, ...). Adds a Core Profile step to the wizard, which owns the inner geometry; see Multi-Lumen Core.
Defaults follow the diameter you enter

Enter the diameter before anything else. VirtuCath opens on a plain 6 Fr polymer tube, and every value the wizard fills in for you is sized from the fixed diameter (the OD in the Fixed OD modes, the ID in Fixed ID, the wall in Fixed OD and Fixed ID): the starting liner and jacket walls, the wall of any layer you add, the wire of any braid or coil you add, its picks per inch, and the pull wire. Change the diameter and those values follow it, silently, down to a set of manufacturing floors (a 0.0005 in wall, a .0005 in x .0025 in braid wire, a 0.001 in pull wire). They never grow past the value a 10 Fr design would get.

Three things stop a value following the diameter: you edit anything on that layer's card (the wire's shape or size, for the pull wire), you click Build, or the design was loaded from a file. After that the value is yours and nothing in the app changes it; if it no longer fits, the page you are on says so instead.

Section Lengths​

  • Label: Provide a descriptive name for the section (e.g., "Distal Tip"). This name identifies the section in reports, data readouts, and exported log files.
  • Length: Specify the length of this catheter section.
  • Color: Choose a distinct color to help identify this section in the 3D viewer. Click the color swatch to open the selection dialog.
  • Section controls: One toolbar acts on the section selected in the list. The Up/Down arrows move it proximally or distally.
  • Add: Inserts a new section after the selected one, toward the distal end. A design holds up to 10 sections.
  • Delete: Deletes the selected section. The Pullring goes only with the pull wires; see Pullring length.

Section 1, the proximal end, is fixed: it never moves, it is never deleted, and nothing is inserted before it.

Color bar preview: The bar at the top of the panel updates as you edit. Each band's width is the section's length and its height the section's OD relative to the rest of the shaft; the lighter band inside it is the bore. An amber mark sits over any joint where the OD or ID steps, and hovering a section gives its OD and ID. Section 1 (the proximal end) is on the left; the distal tip is on the right.

Section-length constraints:

  • Minimum section length: 2 mm (0.12 in), or 0.5 mm for the Pullring.
  • Maximum cumulative catheter length: 1500 mm (59 in).

Pull-Wire Settings​

  • Pullwire arrangement:
    • None: Not steerable.
    • Single Pullwire: Simulates a catheter with one pull wire, typically for uni-directional deflection.
    • Two Opposed Pullwires: Simulates a catheter with two pull wires, oriented 180 degrees apart relative to each other.
    • Four Pullwires: Simulates a catheter with four pull wires, oriented 90 degrees apart relative to each other, allowing for bi-directional steering.
  • Anchor pullwires distal to: Defines the catheter section after which (distal) the pull wires are anchored.
  • Pullwire shape: Select the pull wire wire cross-section (Round or Flat).
  • Pullwire Diameter / Thickness × Width: The wire's cross-section dimensions: diameter for a round wire, thickness × width for a flat wire. Together with the pull-wire material, this sets the wire's physical stretch stiffness. Until you edit it, the wire is sized from the diameter and the arrangement (0.010 in at 10 Fr, 0.0015 in at 020), always small enough to fit; choosing an arrangement does not count as editing it.
  • When a pull wire cannot fit: a wire you typed that is too large for the geometry is reported in the Action Required box on this step, with the largest size that fits: for example, The pull wires are too large for a 0.0200 in OD. With four pull wires, 'Pullwire diameter' can be at most 0.0072 in; it is 0.0080 in. Each lumen is the wire plus 0.0010 in clearance. Choose a thinner wire, fewer pull wires, or a larger Outer diameter. The limit uses this step's inputs only, the fixed diameter and the arrangement; the section pages check the wire against their own layer stacks.
  • Pullwire material: The wire's material, which supplies the Young's modulus for the stretch stiffness. Defaults to 304V (Spring Temper). Like the braid and coil wire dropdowns, this list shows metals only until you pick More materials… at the bottom. Lumen liners (none, a polymer tube, or a closed metal coil with an optional polymer jacket) are configured and previewed per section on the Construction pages.
  • Pullring length: A steerable design always has a Pullring section, the short metal tube the pull wires end in. It is added with the pull wires, sits just distal of the anchor and moves with it, and is removed only by setting Pullwire arrangement to None. It starts at 3 mm (1/8 in) and can be 0.5 to 25.4 mm long, and it matches the OD and bore of the section before it. The tube itself is set on the Construction page.

The pull ring sits under the jacket, so views of the outside of the catheter do not show it: the Drawing side view and the Pushability plot paint it in its neighbor's color. Kink Radius does not apply to it and reports N/A.

On multi-lumen core designs, the core's shape and its rotation relative to the pull-wire layout are set on the Core Profile step. Pull wires are never routed through the core; they run in the wall stack above it, and the wizard keeps the pull-wire offset clear of the core OD automatically. See Multi-Lumen Core.