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BLBlender

STMap Exporter

by K_Naoki·VFX

Images © K_Naoki. Used for product review; image policy.

Why we like it

Stands out in the blender_extensions library for bridging Blender's camera solve to external compositors with pixel-accurate distortion maps.

What is STMap Exporter?

STMap Exporter reads camera lens distortion data from Blender's Movie Clip Editor and writes it out as STMap images. It calculates Blender's internal distortion models — Polynomial, Division, Nuke, and Brown-Conrady — and generates 32-bit Float STMaps. Loading the resulting EXR files into an STMap node in external compositors such as Nuke, Fusion, or Natron lets you apply or remove lens distortion matching Blender's tracking environment with pixel accuracy.

The add-on faithfully replicates Blender's internal normalization scales, principal point shifts, and asymmetric aspect ratios. Overscan can be handled through Auto BBox expansion based on the distortion curve, or through a Custom resolution to align with CG overscan pipelines. One-click operators apply the calculated overscan resolution to the Scene render settings and scale the active camera's sensor width to maintain the exact field of view.

This public release is the version with the Cupy GPU Acceleration feature removed, so exporting high-resolution footage can take tens of seconds to several minutes. A separate GPU-accelerated version is available from the developer. Presets can be saved and loaded directly from the standard Blender panel header.

Who is STMap Exporter best for?

STMap Exporter is best for blender artists tracking footage who need lens distortion exported as STMaps for compositing in Nuke, Fusion, or Natron.

How much does STMap Exporter cost?

STMap Exporter is completely free to download and use.

Key features

  • Exports Undistort and Redistort STMaps, plus optional grayscale checkerboard guide images to visualize the distortion effect
  • Calculates Blender's Polynomial, Division, Nuke, and Brown-Conrady distortion models as 32-bit Float STMaps
  • Replicates Blender's internal normalization scales, principal point shifts, and asymmetric aspect ratios
  • Overscan control via Auto BBox expansion based on the distortion curve, or Custom resolution with percentage scale or explicit pixel dimensions
  • Apply to Scene operators that update render resolution and scale the active camera's sensor width, with a Restore option
  • Preset system for saving and loading configurations from the standard Blender panel header
  • Format options including OpenEXR with 16-bit or 32-bit Float color depth and ZIP lossless compression

Tags

#STMap#lens distortion#camera tracking#compositing#Nuke#OpenEXR#Movie Clip Editor#Blender extension

Frequently asked questions

Does STMap Exporter work with Blender 4.2?

STMap Exporter is compatible with Blender 4.2 LTS and newer. It operates inside the Movie Clip Editor: you track footage and solve the camera and lens distortion in the Lens panel as usual, then open the Sidebar with the N key, navigate to the Track tab, and scroll down to the STMap Exporter panel. From there you set overscan preferences and an output path before exporting. The current version listed here is 1.1.0, last updated on 2026-03-02.

How do I use the exported STMap in Nuke or Natron?

STMap Exporter writes .exr files that plug directly into the UV channel of an STMap node in your compositor. For a Nuke or Natron workflow, load the exported Undistort_STMap and connect a Reformat node to crop it back to your original footage resolution while preserving the bounding box — check preserve bounding box and set resize type to none. This makes the map function exactly like an STMap natively generated by Nuke's LensDistortion node.

Does STMap Exporter support GPU acceleration?

STMap Exporter's public extension version has the Cupy GPU Acceleration feature removed, so exporting high-resolution footage can take tens of seconds to several minutes. A separate GPU-acceleration-enabled version is available from the developer's GitHub repository. If export speed on large footage matters to your pipeline, that GPU build is the alternative to consider; otherwise this version covers the same export models and overscan controls at slower processing times.

Is STMap Exporter free, and what license does it use?

STMap Exporter is listed as free in this catalog. It is distributed under the GNU General Public License v3.0 or later. For current licensing terms, the source code, and the separate GPU-accelerated build, check the developer's page on GitHub. The output format is flexible too — OpenEXR is recommended, with a choice of 16-bit or 32-bit Float color depth, and 32-bit Float is strongly recommended to prevent sub-pixel stepping and banding.

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