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Constant T3D

Summary

The Constant T3D sets every voxel to one colour and alpha. With the first input connected it takes the input's resolution and, by default, multiplies the input by the colour, which makes it a tint or a channel mask; set Operation to Over to replace the input instead. See Combining volumes.

Parameters - Constant Page

Color Colorr Colorg Colorb ⊞ - The colour written to every voxel. RGBA × 3 · default 1

Alpha Alpha - The alpha written to every voxel. Float · default 1

Pre-Multiply RGB by Alpha Premultrgbbyalpha - Multiplies Color by Alpha, giving premultiplied output. Toggle · default On

Parameters - Output Page

Combine with Input Combineinput ⊞ - How the generated volume uses the first input, when one is connected. Menu · default Composite and Set Resolution

  • Set Resolution Only res - The input only sets the output resolution; its content is discarded.
  • Composite and Set Resolution compres - The generated volume is composited with the input using Operation.

Operation Operand ⊞ - Compositing operation between the colour and the first input, with the same options as TouchDesigner's Composite TOP. The default Multiply scales the input's channels by the colour; Over replaces it. Menu · default Multiply

Swap Order Swaporder - Swaps the operands of Operation, so the input comes first. Toggle · default Off

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 - Has no effect on this operator: its shaders are compute shaders, which read the connected input on every pass, so extra passes repeat identical work. Leave it at 1. 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: Composite Input T3D_in1 - Optional. Sets the output resolution when Output Resolution is Use Input, and with Combine with Input at Composite it is combined with the colour using Operation: the default Multiply tints the input.

Operator Outputs

  • Output 0: Output T3D_output - Every voxel set to the colour, or the input combined with it.

Performance

GPU time when the operator recooks: 0.039 ms at 64³, 0.050 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.