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Edge T3D

Summary

The Edge T3D measures how much the selected value (Select) changes around each voxel: the length of its gradient from central differences over one voxel on each side, divided by √3, times Edge Color. Flat regions are 0; the surfaces of shapes, and any sharp transition in a density, light up. Unlike the Edge TOP it outputs the edge strength alone, not composited over the input.

Parameters - Edge Page

Select Select ⊞ - The value whose edges are found, as on the Threshold T3D (luminance is 0.3 R + 0.6 G + 0.1 B). Menu · default Luminance

Edge Color Edgecolorr Edgecolorg Edgecolorb Edgecolora ⊞ - Multiplies the edge strength, colour and alpha. RGBA × 4 · default 1 · range 0 to 1

Extend Inputextenduv ⊞ - What the input returns beyond its faces: with Zero, content touching a face shows an edge there; Hold does not. Menu · default Zero

  • Hold hold
  • Zero zero
  • Repeat repeat
  • Mirror mirror

Parameters - Common Page

Output Resolution Outputresolution ⊞ - Where the output's width, height and depth come from. With nothing connected to the first input the operator always uses Resolution, whichever option is set. Menu · default Use Input

  • Use Input useinput - The first input's width, height and depth.
  • Custom custom - The Resolution parameter.

Resolution Resolution1 Resolution2 Resolution3 ⊞ - Width, height and depth of the output in voxels. Used when Output Resolution is Custom, or when the first input is not connected. Memory is width × height × depth × bytes per voxel of the Pixel Format: 256³ at 16-bit float RGBA is 128 MiB. Int × 3 · default 64 · min 1

Input Smoothness Inputfiltertype ⊞ - Filtering of the internal GLSL TOPs' input samplers, as TouchDesigner's Input Smoothness. Inputs are read at normalised coordinates, so this matters whenever the input and output resolutions differ or an input is transformed. Nearest Pixel returns voxels unblended; Interpolate Pixels is trilinear. Menu · default Interpolate Pixels

  • Nearest Pixel nearest
  • Interpolate Pixels linear
  • Mipmap Pixels mipmap

Passes Npasses - Runs the operation this many times, each pass taking the previous pass's result in place of the first input. Cost scales linearly with the number of passes. Int · default 1

Pixel Format Format ⊞ - Pixel format of the output. Use Input takes the first input's format. With nothing connected, Use Input resolves to 8-bit fixed (RGBA), which clamps values to 0–1 and quantises them to 1/255: set a float format for signed distances, densities above 1, velocities or anything else outside 0–1. Menu · default Use Input

Bypass Bypass - Passes the first input through unchanged and skips the operator's work. With nothing connected the output is a single black voxel. Toggle · default Off

Version Version - T3D version of this operator. Read-only information; include it when reporting a problem. Str

Operator Inputs

  • Input 0: Input T3D_in1 - The volume to find edges in.

Operator Outputs

  • Output 0: Output T3D_output - The edge strength, times Edge Color.

Performance

GPU time when the operator recooks: 0.018 ms at 64³, 0.034 ms at 128³, all of its passes summed (GeForce RTX 4090, TouchDesigner 2025.33230). An operator whose inputs and parameters are unchanged does not recook and costs nothing.