Resize and reposition an image within a target canvas, with independent control over fit mode, tiling, and resampling filter.

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License notice. The pre-built HDA was compiled under a Houdini Indie/Apprentice license. Loading it in a full Houdini FX session will flag the scene as limited-commercial. If you need an unencumbered HDA, build it from source using your own license — instructions below.

Inputs

# Name Description
0 Source Image to scale
1 Size Reference Optional. When Use Size Reference is enabled, this input sets the output canvas resolution

Parameters

Target Resolution

Use Size Reference When enabled, the output resolution is taken from the image connected to input 1 instead of the Scale Mode parameters.

Scale Mode How the output canvas size is determined.

Mode Description
Preset Choose a standard resolution from a menu
Explicit Set Width and Height directly
Uniform Scale the source by a single multiplier
Non-Uniform Scale X and Y independently

Preset (Preset mode) Standard target resolution. Options include 720p, 1080p, 2K, 4K, 8K, DCI 2K, DCI 4K, and square formats (1K, 2K, 4K).

Width / Height (Explicit mode) Output canvas size in pixels.

Constrain Proportions (Explicit mode) Lock the Width/Height ratio to the source aspect.

Scale (Uniform mode) Multiplier applied equally to both axes.

Scale X / Scale Y (Non-Uniform mode) Independent per-axis scale multipliers.

Fit Mode

Controls how the source image is placed inside the output canvas.

Fit Mode

Mode Description
Distort Stretch source to fill canvas exactly, ignoring aspect ratio
Fit Scale source to fit entirely inside canvas, preserving aspect. Remaining area filled with Background Color
Fill Scale source to fill canvas entirely, preserving aspect. Content that extends beyond canvas edges is cropped
Width Scale source so its width matches the canvas width
Height Scale source so its height matches the canvas height
None Place source at 1:1 pixel scale, centered

Background Color (Fit, Width, Height, None modes) Color used to fill any canvas area not covered by the source image.

Examples

Fit — 4:3 source in a 16:9 canvas. Blue fill shows the padding.

Fit mode

Fill — Portrait source cropped to fill a landscape canvas. No padding; edges are clipped.

Fill mode

Distort — Source stretched to fill the canvas without preserving aspect ratio.

Distort mode

Tiling

Controls how the image repeats beyond its placed bounds. Tiling applies in image-pixel space: the source tile is one source-resolution unit in size.

Tile Mode

Mode Description
None No tiling. Areas outside the placed image use Background Color
Repeat Tile the image with simple translation
Mirror X Mirror the image horizontally on each repeat
Mirror Y Mirror the image vertically on each repeat
Mirror Both Mirror on both axes

Tile Offset X / Tile Offset Y (any mode except None) Shift the tile origin in UV space. Values wrap at ±1.

Examples

Repeat — 512×512 source tiled to fill a 1920×1080 canvas.

Tile Repeat

Mirror Both — Same source tiled with bilateral mirroring.

Mirror Both

Resampling

Filter Reconstruction filter used when scaling the source.

Filter Notes
Auto Bilinear for magnification, Catmull-Rom for minification
Point Nearest-neighbour. Fastest; aliased
Bilinear Smooth, slightly soft
Box Simple box filter
Bartlett Triangular filter
Catmull-Rom Sharp, good general-purpose filter
Mitchell Slight blur; reduces ringing vs Catmull-Rom
B-Spline Smoothest; can appear soft

Building from Source

If you need to compile the HDA under your own Houdini license, use the included build script. This produces a fresh scale_cop.hda that carries no license restrictions from a third-party session.

Prerequisites

  • Houdini 20 or later (any edition — Indie, FX, etc.)
  • hython on your PATH, or use the full path to your Houdini installation’s hython

Steps

  1. Download build_scale_cop.py and place it in any working directory.

  2. From a terminal in that directory, run:

    hython build_scale_cop.py

    If hython is not on your PATH, use the full path. For example on Linux:

    /opt/hfs20.5/bin/hython build_scale_cop.py

    On Windows:

    "C:\Program Files\Side Effects Software\Houdini 20.5\bin\hython.exe" build_scale_cop.py

  3. The script writes scale_cop.hda alongside itself in the same directory.

Installing the HDA

In Houdini, go to Assets > Install Asset Library, select scale_cop.hda, and click Install. The node will appear in any COP network as Scale COP.