OTF to RGF Converter

Render OpenType fonts as LEGO Mindstorms display images online

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Mindstorms Display

Turn OTF font glyphs into RGF images that display directly on LEGO Mindstorms EV3 and NXT programmable brick screens.

Creative Projects

Use your own typography on robotic displays. OTF to RGF conversion adds a typographic dimension to LEGO Mindstorms programming.

No Special Tools

Create RGF images from OTF fonts right in your browser. No LEGO software needed for the conversion itself.

How to convert OTF 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

OTF (OpenType Font) is a scalable font format jointly developed by Microsoft and Adobe, announced in 1996 and later standardized as ISO/IEC 14496-22. OpenType unifies TrueType and PostScript font technologies under a single container — OTF files with PostScript outlines use CFF/CFF2 tables for cubic Bezier curves, while those with TrueType outlines use quadratic splines in glyf tables (these typically carry the .ttf extension despite being OpenType). The format supports up to 65,535 glyphs per font, enabling comprehensive coverage of Unicode's vast character repertoire including Latin, Cyrillic, Arabic, CJK, and mathematical symbols within one file. Advanced typographic features are encoded in GSUB (glyph substitution) and GPOS (glyph positioning) tables, powering contextual alternates, ligatures, small caps, stylistic sets, and complex script shaping. A defining advantage is cross-platform consistency — the same OTF file renders identically on Windows, macOS, Linux, iOS, and Android without platform-specific builds. The rich OpenType Layout feature system is another major strength, giving designers fine-grained typographic control that was previously impossible in a single font file. OpenType 1.8 introduced variable font technology, allowing continuous interpolation across weight, width, slant, and custom design axes within a single compact file. Universal support in web browsers, design applications, office suites, and operating systems makes OTF the dominant professional font format in modern digital typography.
Initial release: 1996
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 OTF to RGF?

RGF is the display image format for LEGO Mindstorms bricks. Converting OTF creates glyph graphics that can be shown on EV3 and NXT screens.

How do I use an RGF file?

Upload the RGF file to your LEGO Mindstorms brick via the programming environment. The image displays on the brick LCD during program execution.

What are the dimensions of RGF images?

RGF images match LEGO Mindstorms screen resolution — typically 178x128 pixels for EV3. OTF glyphs are scaled to fit these constraints.

Can I make RGF images from several fonts?

Yes — upload multiple OTF fonts and Convertio produces individual RGF images for each, all processed in one session.

Is this free?

Absolutely free. Convertio converts OTF to RGF online — no robotics software or special tools required.