SK to RGF Converter

Convert SK to RGF online — LEGO robot graphic free

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Robotics Ready

RGF displays on LEGO Mindstorms robots. Convert your SK designs to RGF and show custom graphics on robot screens.

Web-Based

No LEGO development software or Skencil needed. Upload SK files online and receive RGF output from your browser.

Cloud Processed

Convertio servers handle the entire conversion. Your device stays unburdened during the SK to RGF process.

How to convert SK to RGF

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose rgf or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your rgf file right afterwards

About formats

SK is the native file format of Skencil (originally named Sketch), a free vector graphics editor for Linux created by Bernhard Herzog, with the first public release on October 31, 1998. Skencil holds historical significance as one of the earliest full-featured vector drawing applications written almost entirely in Python, with only performance-critical rendering components implemented in C. The SK file format uses a text-based, Python-like syntax to describe document structure — pages, layers, groups, and individual graphic objects are represented as nested statements with parameters specifying coordinates, colors, line styles, and transformations. The format supports Bezier curves, rectangles, ellipses, text objects with font specifications, imported raster images, gradient and pattern fills, and hierarchical grouping with affine transforms. One advantage is human readability — SK files can be opened in any text editor, making it possible to inspect, modify, or generate artwork programmatically using simple scripts. The Python-native structure also provides a benefit for automation: since Skencil itself is a Python application, the file format integrates naturally with scripting workflows for batch processing and procedural graphic generation. While Skencil's development slowed after the mid-2000s, its SK format became the foundation for the sK1 project, which extended the format and continued active open-source vector graphics development. SK files remain convertible through sK1, UniConvertor, and other open-source tools.
Developer: Bernhard Herzog
Initial release: October 31, 1998
RGF (Robot Graphics Format) is a simple monochrome bitmap image format used by LEGO Mindstorms EV3 programmable robotics kits, introduced with the EV3 system on September 1, 2013. RGF files store 1-bit (black and white) images designed for display on the EV3 Intelligent Brick's 178x128 pixel monochrome LCD screen. The format uses a minimal structure: a header containing the image width and height as binary values, followed by the pixel data where each bit represents one pixel (1 for black, 0 for white), packed eight per byte in row-major order. RGF images are used as custom display graphics in EV3 programs — students and hobbyists create them for robot status displays, user interfaces, splash screens, and animation frames shown on the brick's screen during program execution. The images are typically designed using LEGO's EV3 software (which includes a built-in image editor) or converted from other formats using community tools. RGF fits within LEGO's broader educational robotics platform, where the Mindstorms system teaches programming, engineering, and computational thinking to students worldwide. One advantage is the format's role in educational technology: RGF provides a simple, concrete example of how digital images are represented as binary data — a concept that students working with Mindstorms can directly observe by examining the file contents and seeing the corresponding image on the brick's screen. The format's simplicity makes it accessible for young programmers learning about file formats and binary data. RGF files can be created and converted using ImageMagick, the EV3 development environment, and community tools like ev3dev.
Developer: The LEGO Group
Initial release: 2013

Frequently Asked Questions

Why convert SK to RGF?

RGF is the Robot Graphic Format for LEGO Mindstorms displays. Converting SK to RGF creates images displayable on LEGO robot screens.

What uses RGF files?

LEGO Mindstorms NXT and EV3 robots use RGF for on-screen graphics. The format is specific to the LEGO robotics platform.

Is RGF monochrome?

Yes — RGF images are monochrome, matching the pixel display capabilities of LEGO Mindstorms robot screens.

Does conversion resize the image?

RGF images are sized for small robot displays. Your SK artwork is rasterized at dimensions suitable for Mindstorms screens.

Is this free?

Convertio provides free SK to RGF conversion. Premium plans offer expanded capacity for users creating multiple graphics.