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Catheter Setup tab

The catheter setup wizard guides you through defining the geometry and characteristics of your catheter design.

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 of the Setup Wizard. 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.

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: Use the Up/Down arrows to reorder sections.
  • Create New Section: Press the Green Plus button to generate a new section proximal to the selected section.
  • Delete Section: Press the Red X button to delete the selected section.

Color bar preview: A horizontal color bar at the top of the panel auto-updates to reflect the relative lengths of your sections as you edit them. 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).
  • Maximum cumulative catheter length: 1500 mm (59 in).
  • Performance: Define only the flexible or steerable distal portion you intend to simulate. Modeling long catheters can degrade simulation performance.

Pullwire Settings​

  • Pullwire Arrangement:
    • None: Not steerable.
    • Single Pullwire: Simulates a catheter with one pullwire, typically for uni-directional deflection.
    • Two Pullwires: Simulates a catheter with two pullwires, oriented 180 degrees apart relative to each other.
    • Four Pullwires: Simulates a catheter with four pullwires, oriented 90 degrees apart relative to each other, allowing for bi-directional steering.
  • Pullwire Anchoring: Defines the catheter section after which (distal) the pullwires are anchored.
  • Pullwire Shape: Select the pullwire lumen shape (Round or Flat).
  • Pullwire Lumen Size: Enter the inner diameter for round lumens or inner width and thickness for flat lumens.
  • Include Lumen Liners: Use this checkbox to include pullwire lumen liners in the calculation:
    • If unchecked, the lumens are modeled as unlined.
    • If checked, you can select the liner material and wall thickness.

Section Construction​

Define the construction for each catheter section. Each section has its own definition page, accessible from the Setup Wizard's section navigation — switching sections swaps the entire panel to that section's stackup, dimensions, and reinforcement. The panel is organized into the Clone... shortcut and a cross-section preview at the top, a per-section settings strip, the layer stackup editor, and the manual override block at the bottom.

Clone & Match Shortcuts​

In the top-left corner of each section's definition page, the Clone... button opens a menu with two shortcuts that let you quickly align a section to another already-defined section, instead of re-entering every layer by hand:

  • Clone From...: Pick another section in the design and copy its entire construction — layer stackup, materials, reinforcement, pullwire settings, and overrides — into the active section. Useful when you want to carry over a shared liner and braid from another section and then change a single parameter, such as the jacket material.
  • Match Dimension To...: Pick another section in the design and match the active section's outer or inner diameter to that section. A second dialog then asks which layer in the active section to adjust so the new OD or ID is met (typically the jacket). Useful for maintaining a continuous OD across adjacent sections that otherwise have different layer compositions. (Not available in Fixed OD and Fixed ID mode, since all sections already share globally fixed boundaries.)

Both shortcuts only act on the currently active section. Cloned and matched sections are not linked afterward — subsequent edits to the source do not propagate.

Cross-Section Visualizer​

At the top of the panel, a scaled cross-section view displays a dynamic representation of the active section's layers, materials, and internal lumens. The view updates in real time as you modify layer properties.

Section Settings​

Modify the section length and representation color directly from this panel without navigating back to the Section Lengths page.

Layer Stackup​

Layers are defined from the inside out: Layer 1 is the innermost layer (liner) and the final layer is the outermost jacket.

Card controls (per layer):

  • Up/Down arrows swap the active layer with a neighbor.
  • Red "X" deletes the selected layer.
  • Green "+" button inserts a new polymer layer proximal to the selection.

Per-layer properties:

  • Color: Click the color swatch next to the layer name to change its representation in the 3D Viewer and Peel-away Visualizer.

  • Name: An optional label for the layer (e.g., "Outer Jacket," "Braid," "Liner").

  • Adaptive Layer Toggle: Only available when the global design mode is set to "Fixed OD and Fixed ID". Clicking the Adaptive toggle automatically calculates and locks this layer's thickness to satisfy the global inner and outer diameter constraints. Only one layer can be adaptive per section, and it defaults to the outermost polymer layer (Jacket).

    Note: Reinforced layers (Braid/Coil) cannot be adaptive.

  • Material: For polymer layers, select the material from the dropdown. Reinforced layers (Braid/Coil) don't show a material selector — they automatically inherit the polymer from the layer immediately outside (which becomes the matrix material when the catheter is reflowed).

  • Layer Type: Choose the structural type of the layer:

    • Polymer: A pure polymer layer. Innermost and outermost layers must be polymer layers.
    • Braid: A woven wire reinforcement pattern.
    • Coil: A helical wire reinforcement pattern.

  • Thickness:

    • For Non-Reinforced Layers: Enter the wall thickness manually (unless marked as the Adaptive layer).
    • For Reinforced Layers: This field is read-only. The software automatically calculates the thickness based on the wire dimensions (2× wire thickness for Braids, 1× wire thickness for Coils).

  • Dimensions (ID/OD): Displays the calculated Inner Diameter (ID) and Outer Diameter (OD) based on the cumulative thickness of previous layers.

Pullwire Layer Settings​

If Pullwires are enabled in the Global Settings, a special "Pullwires" layer is automatically injected into the stackup. This layer manages the position and space required for the pullwires and their optional liners.

  • Construction Type:
    • Individual Mandrels: Use this setting if the lumens are constructed by individual mandrels prior to reflow. The layer's thickness is automatically calculated based on the pullwire lumen and liner dimensions defined in the global settings. The material is inherited from the layer immediately outside of it.
    • Multi-Lumen Extrusion: Use this setting if the lumens are created with a multi-lumen extrusion. The layer is modeled as a continuous multi-lumen polymer extrusion. You can manually enter the layer thickness (minimum thickness is constrained by the lumen dimensions) and select a polymer material from the library.

Reinforcement Settings​

If "Braid" or "Coil" is selected for a layer, a sub-panel appears to define the wire geometry. A dynamic preview of the pattern (including the calculated braid angle) is displayed.

Common settings:

  • Wire Material: Select the metal (e.g., Stainless Steel, Nitinol) from the material library.
  • Wire Shape: Choose between Round or Flat/Ribbon wire.
  • Wire Dimensions:
    • Round: Enter the wire diameter.
    • Flat: A dropdown of common ribbon sizes is provided for quick selection, or enter a custom thickness and width.

Braid specifics:

  • Picks Per Inch (PPI): The number of wire crossings per inch of length.
  • Number of Carriers: The number of bobbins used in the braiding machine (e.g., 16, 32, 64). The calculations assume one wire per carrier.
  • Calculated Angle: The resulting braid angle relative to the longitudinal axis.

Coil specifics:

  • Pitch: The distance between the center of one wire wrap and the center of the next.

Manual Override Options​

  • Layer Construction: The default selection. The catheter section is constructed from layers, and bulk section properties are calculated automatically.
  • Manual Stiffness: Allows you to manually enter the bulk section properties:
    • Bending Stiffness (EI)
    • Torsional Stiffness (GJ)
  • Rigid Body: The section is modeled as a single, non-deformable rigid body.

Multi-lumen cross-sections:

VirtuCath does not currently support multi-lumen cross-section designs. To simulate a multi-lumen catheter dynamically:

  • Calculate the area moment of inertia of the multi-lumen layer. Asymmetric cross-sections are not supported, so pick the section moment of inertia of interest for the simulation.
  • For a given layer OD, calculate the layer thickness so that the ring segment has the area moment of inertia equivalent to the desired value.
  • Some calculated catheter properties (torsional and axial stiffness, kink radius, burst pressure, etc.) will not be accurate for a simulated multi-lumen catheter.

Alternative methods to determine stiffness values (EI and GJ):

Accurate bending stiffness (EI) and torsional stiffness (GJ) values are essential for a realistic dynamic simulation. If these properties are unknown for your design, here are two common methods to determine them:

1. Calculation from Geometry

Ideal if you have a CAD model of the catheter's cross-section and know the material properties.

  • Bending Stiffness (EI): The material's Young's Modulus (E) multiplied by the cross-section's Area Moment of Inertia (I).
  • Torsional Stiffness (GJ): The material's Shear Modulus (G) multiplied by the cross-section's Polar Moment of Inertia (J).

2. Physical Measurement

Directly testing a physical sample is the most accurate method, as it captures the real-world performance of the manufactured component.

  • Bending Stiffness (EI): Typically found using a three-point bend test, where a known force is applied to a sample and the resulting deflection is measured.
  • Torsional Stiffness (GJ): Found by fixing one end of a sample, applying a known angle of twist at the other end, and measuring the torque.

While high-precision test equipment is ideal, simple benchtop setups can provide reasonable estimates for simulation purposes.

Review & Build​

This is the final step where you can review your design before creating the simulation model.

  • Color Bar: A scaled diagram of your catheter design, with the proximal end on the left and the distal tip on the right. A black line indicates the pullwire termination point.
  • Configuration Summary: Review all entered parameters before building the model. Click the "Edit" link next to any item to return to that section and make changes.
  • Peel-away Illustrations: The illustrations are created parametrically for each section and accurately reflect the scale and composition. To copy the illustration for sharing, right-click and select Copy.
  • Save Config to File: Saves the current catheter design to a file. This allows you to reload the design later or share it with colleagues. This function is also available from the main menu via File > Save Config.
  • Build Model: Click this button to generate the simulation. VirtuCath will build the physics model based on your inputs and automatically load it in the interactive 3D viewer.

JSON schema reference: The catheter .json file follows a versioned schema you can introspect at runtime via the CLI API's export_schema command. This is the canonical reference for the file format and is the best entry point for scripting or AI-agent workflows.