PLT to RAS Converter

Convert HPGL plotter files to Sun Raster image format

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Unix Raster Output

Render PLT plotter drawings as Sun Raster images — native compatibility with Solaris and Unix imaging tools.

Data Privacy

PLT uploads are deleted right after conversion. RAS downloads are removed from Convertio within 24 hours.

Rapid Processing

Cloud infrastructure converts your PLT to RAS in seconds, without tying up your local machine.

How to convert PLT to RAS

1

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

2

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

3

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

About formats

PLT is a vector file format associated with HP-GL (Hewlett-Packard Graphics Language), a plotter control language introduced by Hewlett-Packard in 1977 with the HP-9872 pen plotter. PLT files contain a sequence of two-letter ASCII commands that instruct a pen plotter to move, draw lines, select pens, and render text — commands like PU (pen up), PD (pen down), PA (plot absolute), and SP (select pen) form a straightforward instruction set that directly controls physical drawing motion. The language operates on a coordinate grid measured in plotter units (typically 0.025 mm per unit), and the resulting files read almost like machine code for a drawing device. HP-GL became the dominant standard for computer-aided design output, adopted by virtually every CAD application and supported by plotters from all manufacturers throughout the 1980s and 1990s. One advantage is universal CAD compatibility — PLT files generated by AutoCAD, SolidWorks, or any engineering software can be sent directly to plotters and cutting machines without driver translation. The text-based, human-readable command structure is another strength: engineers can inspect, edit, and hand-write PLT files to troubleshoot output or generate simple drawings programmatically. HP-GL/2, an enhanced version introduced with the HP LaserJet III in 1990, added polygon fills, Bezier curves, and raster support. PLT remains actively used in engineering, architecture, and manufacturing for large-format output.
Developer: Hewlett-Packard
Initial release: 1977
RAS (Sun Raster) is a raster image format developed by Sun Microsystems for their SunOS and Solaris Unix workstations, dating to approximately 1982. Sun Raster files store 2D bitmap images with support for 1-bit monochrome, 8-bit indexed color (with a color map), 24-bit true color (BGR byte order), and 32-bit XBGR (with an unused alpha byte). The format uses a 32-byte header containing a magic number (0x59a66a95), width, height, bit depth, data length, raster type (indicating compression), color map type, and color map length, followed by the optional color map data and the pixel data. RAS supports three encoding modes: standard (uncompressed, with each scanline padded to a 16-bit boundary), byte-encoded (run-length encoded using a simple escape-code scheme), and RGB (uncompressed with RGB rather than BGR byte order). Sun Raster was the native image format for Sun's window system and later the OpenWindows desktop environment, serving as the standard format for screenshots, icons, backgrounds, and application graphics on Sun workstations throughout the 1980s and 1990s. One advantage is the format's representation of Unix workstation computing heritage: Sun Raster files from the SunOS/Solaris era document the visual culture of an important computing platform that drove advances in networking, multiprocessing, and graphics workstation design. The format's straightforward structure is another practical strength — the 32-byte header and simple encoding make RAS files easy to parse and convert, even with custom code. RAS files are supported by ImageMagick, GIMP, XnView, and other image processing tools.
Developer: Sun Microsystems
Initial release: 1982

Frequently Asked Questions

Why convert PLT to RAS?

Sun Raster is native to Unix and Solaris systems — converting PLT makes plotter drawings accessible on those platforms.

What opens RAS files?

GIMP, ImageMagick, XnView, and various Unix/Solaris image viewers handle Sun Raster format natively.

Does RAS support color?

Yes — Sun Raster supports monochrome, indexed color, and RGB true color, accommodating various plotter drawing styles.

Is the rendering accurate?

HPGL paths are rendered faithfully into the RAS pixel format, preserving the drawing layout and proportions.

Is PLT to RAS free?

Yes — Convertio offers free PLT to RAS conversion without registration or payment.

Does this work on Windows?

Absolutely. The converter runs in any browser, regardless of your operating system.