Sigma Graph Custom Node for ComfyUI and Wan-Video

Prototype - Node is in early development, not intended for active use.

A compact, bidirectional editor for sigma schedules used in diffusion sampling.

• 📈 Interactive Graph: Drag points on the graph to shape your sigma schedule.
• ✍️ Text Editing: Edit sigma values directly in the text box – changes are auto-synced.
• 🔁 Apply Changes: Click the ▼ button to apply text changes to the graph.
• 💾 Presets: Save/load custom curve presets with the 💾 button.

Note: On first load the node's UI may render incorrectly (it may appear empty). If this happens, please refresh the page until the issue is resolved. This is a known alpha-stage bug that will be addressed in future updates.

Installation

1. Copy the Folder:
   Copy this folder to your ComfyUI custom nodes directory:
   ComfyUI/custom_nodes/TWanSigmaGraph
2. Restart ComfyUI:
   Restart ComfyUI so that it can register the new node.
3. Locate the Node:
   In the ComfyUI interface, find SigmaGraphNode under the sampling → custom category.

How to Use

1. Set Steps:
   Adjust the steps input to define the number of sampling steps. The output sigma tensor will contain steps + 1 values.
2. Design Your Curve:
   Use either the interactive graph or the text box to shape your sigma curve.
3. Apply & Sync:
   • Click the ▼ button to apply the sigma values from the text box to update the graph.
   • The graph and the text box are automatically synced.
4. Connect the Output:
   Connect the output labeled SIGMAS to your preferred diffusion sampler (e.g., KSampler) that supports external sigma schedules.
5. Save Presets (Optional):
   • Toggle the save mode using the 💾 button.
   • Click on a preset slot to save the current curve or load a previously saved curve.

File Overview

| File | Purpose | |------------------------------|------------------------------------------------------------------------| | __init__.py | Registers the node and instructs ComfyUI where to find the widget code | | TWanSigmaGraph.py | Contains the backend logic to generate the sigma tensor schedule | | js/TWanSigmaGraphWidget.js | Implements the custom graph widget UI (drag, sync, and presets) |

Troubleshooting

• Node Not Rendering Correctly:
  On the first load, the node’s widget may sometimes render incorrectly (e.g., it might appear empty). Simply refresh the page until the widget appears as expected.
• Empty or Incorrect Presets:
  Ensure that your browser’s local storage is not blocking data saves if presets aren’t showing.

Thanks

• Realistic_Studio_930:
  For introducing the concept of sigma schedules and inspiring the graph’s design.
• huchenlei:
  For providing invaluable guidance and reviewing the JavaScript implementation.
• Google & OpenAI:
  Special thanks to Gemini 2.5 Pro and ChatGPT, which were instrumental in refining the development process.

License

This project is released under the MIT License. See the LICENSE.txt file for details.