ComfyUI-3D-RGB-Histogram

ComfyUI 3D RGB Histogram

A ComfyUI custom node that renders an interactive 3D RGB color histogram of an image directly on the node, using Three.js.

Each point in the cube represents a color bucket; its position encodes the R/G/B values, and its color shows either the actual RGB color or the bucket frequency (density).

Features

• Interactive 3D histogram rendered on the node
• Orbit and zoom the cube directly with the mouse
• Toggle axis, bounding box, and floor grid overlays
• Switch between RGB and Density coloring modes
• Works fully offline with bundled Three.js

Installation

Manual

1. Clone this repository into your ComfyUI/custom_nodes/ folder:

   cd ComfyUI/custom_nodes
   git clone https://github.com/petrvavrin/ComfyUI-3D-RGB-Histogram.git
   

2. Install the Python dependencies:

   python_embeded\python.exe -m pip install -r ComfyUI\custom_nodes\ComfyUI-3D-RGB-Histogram\requirements.txt
   

3. Restart ComfyUI.

The node ships with a vendored copy of Three.js (r128) under web/lib/, so it works fully offline as long as that file is present.

Usage

Add the 3D RGB Histogram Viewer node (category image/analysis) and connect an IMAGE output to it. The node has no outputs of its own; it renders an interactive preview widget directly on the node.

Controls:

• Drag with the mouse to orbit the cube
• Scroll to zoom in/out

Parameters:

| Parameter | Default | Description | |---|---|---| | bins | 24 | Number of buckets per color channel (higher = more detail, slower) | | point_size | 14 | Size of each point in the cube | | cube_scale | 78 | Overall scale of the histogram cube | | color_mode | RGB | RGB colors points by their actual color; Density colors by how frequently that color appears | | auto_rotate | False | Slowly spin the cube automatically | | show_axes | True | Show the R/G/B axis indicators | | show_box | True | Show the bounding box edges | | show_floor | True | Show the floor grid |

Notes

• Only the first image of a batch is visualized.
• Preview images are written to ComfyUI's temp directory as rgb_histogram_3d_temp_<node_id>.png.
• Each node overwrites its own file on every run, so files do not pile up during a session.
• Leftover files from a previous session are cleaned up when ComfyUI starts.

Troubleshooting

• If the node does not appear after installation, restart ComfyUI.
• Verify the repository is installed under ComfyUI/custom_nodes/.
• If the histogram does not render, ensure the connected input is a valid IMAGE output.

License

MIT. Bundled Three.js (web/lib/three.min.js, r128) is also MIT-licensed, © Three.js Authors.