SFD to RGF Converter

Render FontForge fonts as LEGO Mindstorms display images

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Robotics Ready

Turn your SFD font designs into RGF images that display directly on LEGO Mindstorms brick screens — a creative crossover of typography and robotics.

No Local Tools

Convertio handles SFD to RGF rendering on its servers. You only need a browser to create Mindstorms display images.

Instant Results

RGF is a tiny monochrome format — conversion finishes almost instantly on Convertio servers.

How to convert SFD 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

SFD (SplineFont Database) is the native source file format of FontForge, the free and open-source font editor originally created by George Williams in 2000 under the name PfaEdit. The format stores a complete font project — glyph outlines (cubic and quadratic splines), advance widths, side bearings, hinting instructions, kerning and OpenType feature tables, naming records, and metadata — in a single human-readable text file. Each glyph is described by its Unicode code point, outline coordinates, reference composites, and anchors, making the entire font design inspectable and diffable with standard text tools. SFD functions as the editable working format during font development, from which finished fonts are compiled to binary formats like OTF, TTF, or WOFF. A primary advantage is version control friendliness — because SFD is plain text, font designers can track changes to individual glyphs, merge contributions from collaborators, and maintain full revision history using Git or any other VCS. The format's completeness is another strength: it preserves every piece of data that FontForge can represent, including TrueType instructions, contextual substitution lookups, and multiple master axes, avoiding round-trip data loss during editing. The SFD specification is publicly documented and has evolved through several versions. FontForge's widespread adoption in the open-source type design community means SFD serves as the source format for hundreds of freely licensed font families distributed worldwide.
Developer: George Williams
Initial release: November 7, 2000
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 SFD to RGF?

RGF is the display format for LEGO Mindstorms NXT/EV3 screens. Convert SFD font glyphs to RGF for custom text and icons on your robot display.

How do I open an RGF file?

RGF files are loaded into LEGO Mindstorms programming environments. They display on the small monochrome NXT or EV3 brick screens.

What resolution does RGF support?

RGF targets the Mindstorms brick display — typically 100x64 pixels on NXT. Glyphs are scaled to fit this compact screen size.

Is RGF only monochrome?

Yes, RGF is a 1-bit format matching the monochrome LCD on LEGO Mindstorms bricks. Each pixel is either on or off.

Is the conversion free?

Convertio converts SFD to RGF for free online — no LEGO software or FontForge needed on your device.