Procedural Cables in Blender Geometry Nodes

This guide explains how to generate fully procedural, hanging cables and wires in Blender using Geometry Nodes. You will learn how to create a flexible curve setup between endpoints, apply realistic gravitational sag using math and curve parameters, convert the curve into a 3D mesh, and expose controls for instant scene customization.

Step 1: Initialize the Geometry Nodes Setup

  1. Add a basic mesh object (such as a default Cube or a Plane) to your scene.
  2. Open the Geometry Nodes workspace and click New to create a new node tree.
  3. Replace or disconnect the default Group Input geometry if you want to generate the cable between specific coordinates, or keep it if you plan to draw curves manually.

Step 2: Generate the Base Curve

To create a cable between two points procedurally:

  1. Add a Curve Line node (Shift + A > Curve > Primitives > Curve Line).
  2. Connect the outputs of the Group Input node to the Start and End inputs of the Curve Line node so you can control the terminal points directly from the modifier panel.
  3. Add a Resample Curve node and set the mode to Count (e.g., 32 or 64 points) to provide enough geometry for smooth deformation.

Step 3: Add Gravitational Sag

To make the cable droop naturally like a catenary or parabolic curve:

  1. Add a Set Position node after the Resample Curve node.
  2. Add a Spline Parameter node and use the Factor output. The factor ranges from 0 at the start of the curve to 1 at the end.
  3. Connect the Factor output to a Float Curve node.
  4. Shape the Float Curve into an inverted arc: keep the start point (0) and end point (1) at a value of 0, and pull down the middle point (0.5) to a negative value (e.g., -1.0).
  5. Add a Combine XYZ node. Plug the output of the Float Curve into the Z input.
  6. Add a Math (Multiply) node between the Float Curve and the Combine XYZ node to serve as a Sag Intensity slider.
  7. Plug the vector output of the Combine XYZ node into the Offset input of the Set Position node.

Step 4: Add Random Noise and Twisting (Optional)

For messy or bundled wires:

  1. Add a Noise Texture node.
  2. Subtract 0.5 from the noise texture using a Vector Math (Subtract) node to center the displacement.
  3. Multiply the noise vector by another Math / Vector Math node to control the strength.
  4. Multiply this noise with the existing sag vector or add it to the Offset of the Set Position node.

Step 5: Convert the Curve to a 3D Mesh

  1. Add a Curve to Mesh node after the Set Position node.
  2. Add a Curve Circle node and connect its output to the Profile Curve input of the Curve to Mesh node.
  3. Adjust the Radius of the Curve Circle (e.g., 0.02m) to define wire thickness.
  4. Set the Resolution of the Curve Circle to 8 or 12 for optimal performance.

Step 6: Assign Materials and Expose Inputs

  1. Add a Set Material node at the end of the node chain and select your desired wire material.
  2. Connect the Sag Intensity (Multiply node), Cable Radius (Curve Circle Radius), and Resolution inputs to blank slots on the Group Input node.
  3. Connect the final mesh output to the Group Output node.

You now have a fully procedural cable generator accessible directly from the Blender Modifier panel, allowing dynamic adjustment of wire sag, thickness, and positioning in real time.